Title: Algebra 1 A Review and Summary Gabriel Grahek
1Algebra 1 A Review and SummaryGabriel Grahek
2In the next slides you will reviewSolving 1st
power equations in one variableA. Special cases
where variables cancel to get all reals or
B. Equations containing fractional
coefficientsC. Equations with variables in the
denominator (throw out answers that cause
division by zero)
31st Power Equations
- Any type of equation that has only one variable.
- x38 4(x2-2)836
- x3-38 (4x2-8)836
- x5 4x2-828
- 4x236
- x29
- x3
Note that the variable can be on both sides.
41st Power Equations
- 3x-412x 4y1624
- 3x-44124x 4y16-1624-16
- 3x16x 4y8
- 3x-x16x-x y2
- 2x16
- x8
51st Power Equations
- Special cases- Ø and all reals
x-(4-3)x 4x42(2x2) x-1x 4x4x -10
xx Ø
61st Power Equations
- Equations containing fractional coefficients and
with variables in the denominator.
7In the next slides you will reviewReview all
the Properties and then take a Quiz on
identifying the Property Names
8Addition Property (of Equality)
Example If a, b, and c, are any real numbers,
and ab, then acbc and cacbIf the same
number is added to equal numbers, the sums are
equal.
Multiplication Property (of Equality)
Example If a, b, and c are real numbers, and
ab, then cacb and acbc. If equal numbers are
multiplied by the same number, the products are
equal.
9Reflexive Property (of Equality)
Example For all real numbers a, b, and caa
Symmetric Property (of Equality)
Example For all real numbers a, b, and cIf
ab, then ba.
Transitive Property (of Equality)
Example For all real numbers a, b, and cIf
ab and bc, then ac.
10Associative Property of Addition
Example For all real numbers a, b, and
c(ab)ca(bc) Example (56)75(67)
Associative Property of Multiplication
Example For all real numbers a, b, and
c (ab)ca(bc) Example
11Commutative Property of Addition
Example For all real numbers a and babba
Example 2332
Commutative Property of Multiplication
ExampleFor all real numbers a, b, and cabba
Example
12Distributive Property (of Multiplication over
Addition)
Example For all real numbers a, b, and
ca(bc)abacand(bc)abaca
13Prop of Opposites or Inverse Property of Addition
Example For every real number a, there is a
real number -a such thata(-a)0 and (-a)a0
Prop of Reciprocals or Inverse Prop. of
Multiplication
Example If we multiply a number times
its reciprocal, it will equal one. For example
14Identity Property of Addition
Example There is a unique real number 0 such
that for every real number a, a 0 a and 0 a
a Zero is called the identity element of
addition.
Identity Property of Multiplication
Example There is a unique real number 1 such
that for every real number a, a 1 a and 1 a
a One is called the identity element of
multiplication.
15Multiplicative Property of Zero
Example For every real number a, a 0 0 and
0 a 0
Closure Property of Addition
Example Closure property of real number
addition states that the sum of any two real
numbers equals another real number.
Closure Property of Multiplication
Example Closure property of real number
multiplication states that the product of any two
real numbers equals another real number.
16Product of Powers Property
Example This property states that to multiply
powers having the same base, add the
exponents.That is, for a real number non-zero a
and two integers m and n, am an amn.
Power of a Product Property
Example This property states that the power of
a product can be obtained by finding the powers
of each factor and multiplying them. That is,
for any two non-zero real numbers a and b and any
integer m, (ab)m am bm.
Power of a Power Property
Example This property states that the power of
a power can be found by multiplying the
exponents.That is, for a non-zero real number a
and two integers m and n, (am)n amn.
17Quotient of Powers Property
Example This property states that to divide
powers having the same base, subtract the
exponents.That is, for a non-zero real number a
and two integers m and n, .
Power of a Quotient Property
Example This property states that the power of
a quotient can be obtained by finding the powers
of numerator and denominator and dividing them.
That is, for any two non-zero real numbers a and
b and any integer m,
18Zero Power Property
Example Any number raised to the zero power is
equal to 1.
Negative Power Property
Example Change the number to its reciprocal.
19Zero Product Property
Example Zero - Product Property states that if
the product of two factors is zero, then at least
one of the factors must be zero. If xy 0, then
x 0 or y 0.
20Product of Roots Property
For all positive real numbers a and b, That
is, the square root of the product is the same as
the product of the square roots.
Quotient of Roots Property
For all positive real numbers a and b, b ? 0
The square root of the quotient is the same as
the quotient of the square roots.
21Root of a Power Property
Example
Power of a Root Property
Example
22Now you will take a quiz!Look at the sample
problem and give the name of the property
illustrated.
Click when youre ready to see the answer.
1. a b b a
Answer Commutative Property (of Addition)
23Now you will take a quiz!Look at the sample
problem and give the name of the property
illustrated.
Click when youre ready to see the answer.
2. am an amn
Answer Product of Powers
24Now you will take a quiz!Look at the sample
problem and give the name of the property
illustrated.
Click when youre ready to see the answer.
3. For every real number a, a 0 0 and 0 a
0
Answer Multiplicative Property of Zero
25Now you will take a quiz!Look at the sample
problem and give the name of the property
illustrated.
Click when youre ready to see the answer.
4. the sum of any two real numbers equals another
real number.
Answer Closure Property of Addition
26Now you will take a quiz!Look at the sample
problem and give the name of the property
illustrated.
Click when youre ready to see the answer.
5. There is a unique real number 1 such that for
every real number a, a 1 a and 1 a a
Answer Identity property of Multiplication
27Now you will take a quiz!Look at the sample
problem and give the name of the property
illustrated.
Click when youre ready to see the answer.
6.
Answer Zero Power Property
28Now you will take a quiz!Look at the sample
problem and give the name of the property
illustrated.
Click when youre ready to see the answer.
7.
Answer Quotient of Powers Property
29Now you will take a quiz!Look at the sample
problem and give the name of the property
illustrated.
Click when youre ready to see the answer.
8. (ab)m am
Answer Power of a Product
30Now you will take a quiz!Look at the sample
problem and give the name of the property
illustrated.
Click when youre ready to see the answer.
9.
Answer Negative Power Property
31Now you will take a quiz!Look at the sample
problem and give the name of the property
illustrated.
Click when youre ready to see the answer.
10.
Answer Prop of Reciprocals or Inverse Prop.
of Multiplication
32Now you will take a quiz!Look at the sample
problem and give the name of the property
illustrated.
Click when youre ready to see the answer.
11. (ab)ca(bc)
Answer Associative Property of Multiplication
33Solving Inequalities
34Solving Inequalities
- Remember the Multiplication Property of
Inequality! If you multiply or divide by a
negative, you must reverse the inequality sign.
-2x lt 8
x gt -4
Solution Set x x gt -4
Graph of the Solution
35Solving Inequalities
- Open endpoint for these symbols gt lt
- Closed endpoint for these symbols or
- Conjunction must satisfy both conditions
- Conjunction AND
x -5 lt x 8
Click to see solution graph
36Solving Inequalities
- Open endpoint for these symbols gt lt
- Closed endpoint for these symbols or
- Disjunction must satisfy either one or both of
the conditions - Disjunction OR
-
x x lt -6 or x 8
Click to see solution graph
37Solving Inequalities Special Cases
- Watch for special cases
- No solutions that work Answer is Ø
- Every number works Answer is reals
- When the disjunction goes the same way you use
one arrow.
x x gt -6 or x 8
Click to see solution graph
38Solving Inequalities Special Cases
- Watch for special cases
- No solutions that work Answer is Ø
- Every number works Answer is reals
-
x -2x lt -4 and -9x 18
Click to see solution
39Solving Inequalities
2x gt 6 or -16x 32
Click to see solution and graph
-2 lt x or x 3
40Solving Inequalities
- Now you try this problem.
-
4x-8 lt 12 and -x lt 10-4
Click to see solution and graph
-6 lt x lt 5
41Type the answer here. Set to fade-in on click
Type a sample problem here. Blah blah blah. You
can duplicate this slide.
Click when ready to see the answer.
Type any needed explanation or tips here. Set to
fade-in 3 seconds after the answer appears above.
42In the next slides you will reviewLinear
equations in two variables Lots to cover here
slopes of all types of lines equations of all
types of lines, standard/general form,
point-slope form, how to graph, how to find
intercepts, how and when to use the point-slope
formula, etc. Remember you can make lovely
graphs in Geometer's Sketchpad and copy and paste
them into PPT.
43Linear Equations
- Slope
- Point-Slope Formula
- Slope-Intercept Formula
- Midpoint Formula
- Standard/ General Form AxBxC
- Distance Between Two Points Formula
44Slope
Pt-Slope Formula
(9,12) and (13, 20) Use when you only have
solution points.
- (9,12) and (13, 20)
- Would be negative if it had a negative sign in
front of it. It would then be a falling line and
not a rising line.
45Midpoint
Distance
(9,12) and (13, 20) Use to find the Distance
between to points.
- (9,12) and (13, 20)
- Use to find the middle point on a line.
46Equations in Two Variables
- The pairs of numbers that come out for each
variable can be written as an (x,y) value.
(ordered pair) - You give the solutions in alphabetical order of
the variables. So, it would be (a,b) and not
(b,a).
47Standard Form
- axbyc
- All linear equations can be written in this form.
- A, b, and c are real numbers and a and b are
non-zero. A, b, and c are integers. - To change to slope intercept
- Axbxc bxaxc
48How to graph
- To graph the slope-intercept form you can take
the y intercept and use the slope to determine
the points on the line. - To graph the standard form you have to change it
to slope-intercept, explained in the last slide,
and then graph it.
49To find the y-intercept
To find the x-intercept
F(x)mxb Set f(x)0 0mxb Divide
out Example F(x)4x-8 04x-8 84x 2x
- F(x)mxb
- Set x to 0
- Fb
- Example
- F(x)4x6
- F(0)4(0)6
- F6
50In the next slides you will reviewLinear
Systems A. Substitution Method B.
Addition/Subtraction Method (Elimination ) C.
Check for understanding of the terms dependent,
inconsistent and consistent
51When two line share solution points
- Null set (if they are parallel)
- This will be called an INCONSISTENT SYSTEM
- One point (if they cross)
- This will be called a CONSISTENT SYSTEM
- Infinite Set or All Pts on the Line (if same line
is used twice) - This will be called a DEPENDENT SYSTEM (It is
also consistent. Dependent is the better name
for it than consistent.)
52- Solution Null set (if they are parallel)
- INCONSISTENT SYSTEM
- One point (if they cross)
- CONSISTENT SYSTEM
- Infinite Set or All Pts on the Line (if same line
is used twice) - DEPENDENT SYSTEM
53The SOLUTION of a SYSTEM is the INTERSECTION SET
Where do the two lines Meet intersect.
54Two Different Equation on the same graph are
called a SYSTEM OF EQUATIONS.
55Method 1 To estimate the solution of a system,
you have to find out where they intersect.
Solution to this system is (2, 1)
56Example You can use Trace on a graphing
calculator to help you estimate the solution of a
system. It can find where they intersect.
57Example You can use Trace on a graphing
calculator to help you estimate the solution of a
system. It can find where they intersect
Solution to this system appears to include TWO
pts (-2.38, 1.79), (3, 0)
58Summary of Method 1 Estimate the SOLUTION of a
SYSTEM on a graph. (Goal Find intersection
pts.)
Disadvantages Might only give an estimate. It
might not be possible to graph some equations
yet. AdvantagesIf the graph is easy, this is a
good way to check. It is good for a quick answer.
59Method 2 Substitution Method(Goal Replace
one variable in one equation with the set from
another.)
Step 1 Look for a variable with a coefficient
of one. Step 2 Move everything else to the
other side. Equation A now becomes y
15-x Step 3 SUBSTITUTE this expression into
that variable in Equation B Equation B now
becomes 4x 3( 15-x ) 38 Step 4 Solve the
equation. Step 5 Back-substitute this coordinate
into Step 2 to find the other coordinate. (Or
plug into any equation but step 2 is easiest!)
60Method 2 Substitution (Goal replace one
variablewith an equal expression.)
Step 1 Look for a variable with a coefficient
of one. Step 2 Isolate that variable
Equation A now becomes y 3x
1 Step 3 SUBSTITUTE this expression into that
variable in Equation B Equation B becomes
7x 2( 3x 1 ) - 4 Step 4 Solve
for the remaining variable Step
5 Back-substitute this coordinate into Step 2 to
find the other coordinate. (Or plug into any
equation but step 2 is easiest!)
61Example Substitution (Goal replace one
variable with the set of another equation.)
Step 1 Look for a variable with a coefficient
of one. Step 2 Move everything else to the
other side. Step 3 SUBSTITUTE this
expression into that variable in Equation B
Step 4 Solve for the remaining variable Step
5 Back-substitute this coordinate into Step 2 to
find the other coordinate. (Or plug into any
equation but step 2 is easiest!)
62Example Substitution (Goal replace one
variablewith an equal expression.)
Step 1 Look for a variable with a coefficient
of one. Step 2 Isolate that variable Step 3
SUBSTITUTE this expression into that variable in
Equation B Step 4 Solve for the remaining
variable Step 5 Back-substitute this coordinate
into Step 2 to find the other coordinate. (Or
plug into any equation but step 2 is easiest!)
63Method 2 Summary Substitution Method(Goal
replace one variable with an equal expression.)
Disadvantages Avoid this method when it
requires messy fractions ? Avoid IF no
coefficient equals one. AdvantagesThis is
the algebra method to use when degrees of the
equations are not equal.
64Method 3 Elimination Methodor
Addition/Subtraction Method(Goal Combine
equations to cancel out one variable.)
Step 1 Look for the LCM of the coefficients on
either x or y. (Opposite signs are recommended
to avoid errors.) Here -3y and 2y could be
turned into -6y and 6y Step 2 Multiply each
equation by the necessary factor. Equation A now
becomes 10x 6y 10 Equation B
now becomes 9x 6y -48 Step 3 ADD the two
equations if using opposite signs (if not,
subtract) Step 4 Solve the equation. Step
5 Back-substitute this coordinate into any
equation to find the other coordinate. (Look for
easiest coefficients to work with.)
65Method 3 Elimination or Addition/Subtraction
Method(Goal Combine equations to cancel out
one variable.)
Step 1 Look for the LCM of the coefficients on
either x or y. (Opposite signs are recommended
to avoid errors.) Here -3y and 2y could be
turned into -6y and 6y Step 2 Multiply each
equation by the necessary factor. A becomes
10x 6y 10 B becomes 9x 6y -32 Step 3
ADD the two equations if using opposite signs (if
not, subtract) Step 4 Solve for the remaining
variable Step 5 Back-substitute this coordinate
into any equation to find the other coordinate.
(Look for easiest coefficients to work with.)
66Method 3 Elimination or Addition/Subtraction
Method(Goal Combine equations to cancel out
one variable.)
Step 1 Look for the LCM of the coefficients on
either x or y. (Opposite signs are recommended
to avoid errors.) Step 2 Multiply each
equation by the necessary factor. Step 3 ADD
the two equations if using opposite signs (if
not, subtract) Step 4 Solve for the remaining
variable Step 5 Back-substitute this coordinate
into any equation to find the other coordinate.
(Look for easiest coefficients to work with.)
67Example Elimination or Addition/Subtraction
Method(Goal Combine equations to cancel out
one variable.)
Step 1 Look for the LCM of the coefficients on
either x or y. (Opposite signs are recommended
to avoid errors.) Step 2 Multiply each
equation by the necessary factor. Step 3 ADD
the two equations if using opposite signs (if
not, subtract) Step 4 Solve for the remaining
variable Step 5 Back-substitute this coordinate
into any equation to find the other coordinate.
(Look for easiest coefficients to work with.)
68Example Elimination or Addition/Subtraction
Method(Goal Combine equations to cancel out
one variable.)
Step 1 Look for the LCM of the coefficients on
either x or y. (Opposite signs are recommended
to avoid errors.) Step 2 Multiply each
equation by the necessary factor. Step 3 ADD
the two equations if using opposite signs (if
not, subtract) Step 4 Solve for the remaining
variable Step 5 Back-substitute this coordinate
into any equation to find the other coordinate.
(Look for easiest coefficients to work with.)
69Method 3 Summary Elimination Methodor
Addition/Subtraction Method(Goal Combine
equations to cancel out one variable.)
Disadvantages Avoid this method if degrees
and/or formats of the equations do not match.
AdvantagesSimilar to getting an LCD, so this
is intuitive, and uses only integers until the
end of the problem.
70Three MethodsMethod 1 Graphing MethodMethod
2 Substitution MethodMethod 3 Elimination
Method or Addition/Subtractio
n Method
71Factoring
- Factor GCF ? for any terms
- Difference of Squares ? binomials
- Sum or Difference of Cubes ? binomials
- PST (Perfect Square Trinomial) ? trinomials
- Reverse of FOIL ? trinomials
- Factor by Grouping ? usually for 4 or more terms
72GCF
- 3x2-9x2
- 3x2(1-3)
- Take out what the two side share in common to
simplify.
73GCF
3(1-6)26(1-6)2
3(1-6)2(13)
You can take out a glob and then combine with the
other globs.
Hint Remember that a glob can be part of your
GCF.
74Difference of Squares
Recall these binomials are called conjugates.
75IMPORTANT!
- Remember that the difference of squares factors
into conjugates . . . - The SUM of squares is PRIME cannot be factored.
- a2 b2 ? PRIME
- a2 b2 ? (a b)(a b)
76Sum/Difference of Cubes
77Sum/Difference of Cubes
- x3 - y3
- (x - y) ( )
- Cube roots w/ original
- sign in the middle
78Sum/Difference of Cubes
- x3 - y3
- (x - y) (x2 y2)
- Squares of those cube roots.
- Note that squares will always be positive.
79Sum/Difference of Cubes
- x3 - y3
- (x - y) (x2 xy y2)
- The opposite of the product
- of the cube roots
80Sum/Difference of Cubes
- x3 - 8
- (x - 2)
- Cube roots of each Squares of those cube roots
- with same sign opp of product of roots in
middle
(x2 4)
2x
81Special Case- 1ststep Diff of Squares
2nd step Sum/Diff of Cubes
- x6 64y6
- ( ) ( )
- ( )( ) ( )(
)
82Special Case 1ststep Diff of Squares
2nd step Sum/Diff of Cubes
- x6 64y6
- (x3 8y3) (x3 8y3)
- ( )( ) ( )(
)
83Special Case 1ststep Diff of Squares
2nd step Sum/Diff of Cubes
- x6 64y6
- (x3 8y3) (x3 8y3)
-
- (x2y)(x22xy4y2) (x2y)(x2-2xy4y2)
84PST
- x2-10x25
- (x-5)(x-5)
- (x-5)2
- Recall PST test
- If 1st 3rd terms are squares and the middle
term is twice the product of their square roots.
85PST
- x2-2416
- (3x-4)(3x-4)
- Conjugates
86Reverse FOIL (Trial Error)
- 12x2-45x42
- (3x-6)(4x-7)
- Conjugates
87Reverse FOIL(Trial Error)
- Hint dont forget to read the signs
- ax2 bx c ? ( )( )
- ax2 bx c ? ( )( )
- ax2 bx c ? ( )( )
- positive
product has larger value - ax2 bx c ? ( )( )
- negative
product has larger value
88Example 11 Factor by Grouping(4 or more terms)
89Example 11 Factor by Grouping(4 or more terms)
- 8x-2y16x-4y
- 2(4x-y)4(4x-y)
- (4x-y)2(24)
2X2
90Factor by Grouping 3 X 1
- x2xyy2-4x2
- (x-y)(x-y)-4x2
- (x-y)-2x(x-y)-2x
91Factor by Grouping 3 X 1
x2-1025-4x2 (x-5)(x-5)-4x2 (x-5)-2x(x-5)-2x
92Rational Expressions
93Rational Numbers
- Thinking back to when you were dealing with
whole-number fractions, one of the first things
you did was simplify them You "cancelled off"
factors which were in common between the
numerator and denominator. You could do this
because dividing any number by itself gives you
just "1", and you can ignore factors of "1". - Using the same reasoning and methods, let's
simplify some rational expressions. - Simplify the following expression
-
- To simplify a numerical fraction, I would cancel
off any common numerical factors. For this
rational expression (this polynomial fraction), I
can similarly cancel off any common numerical or
variable factors. - The numerator factors as (2)(x) the denominator
factors as (x)(x). Anything divided by itself is
just "1", so I can cross out any factors common
to both the numerator and the denominator.
Considering the factors in this particular
fraction, I get -
- Then the simplified form of the expression is
-
94Additoin and Subtraction of Rational Numbers
- 3 5 8
(2)(4) 2
20
20 20 (4)(5)
5 - Notice the steps we have done to solve this
problem. We first combined the numerators since
the denominators are the same. Then we factored
both the numerator and denominator and finally we
cross cancelled.
95Multiplication And Division of Rational Numbers
- x2 - y2 is a rational
expression.(x - y)2 To simplify, we just
factor and cancel - (x - y)(x y) x y
(x - y)2
x - y
96 97Quadratic Equations
- A quadratic equation is an equation that can be
written in this form. - ax2bxc0
- The a,b, and c here represent real number
coefficients. So this means we are talking about
an equation that is a constant times the variable
squared plus a constant times the variable plus a
constant equals zero, where the coefficient a on
the variable squared can't be zero, because if it
were then it would be a linear equation.
98Completing the Square
- a² 2ab b²(a b)².The technique is valid
only when 1 is the coefficient of x². - 1) Transpose the constant term to the rightx²
6x -2 - 2) Add a square number to both sides. Add the
square of half the coefficient of x. In this
case, add the square of 3x² 6x 9 -2 9. - The left-hand side is now the perfect square of
(x 3). - (x 3)² 7.
- 3 is half of the coefficient 6.
- This equation has the form
- a² b which implies a .
Therefore,x 3 - x -3 .
- That is, the solutions to
- x² 6x 2 0
- are the conjugate pair,
- -3 , -3 - .
99Quadratic Formula
100Quadratic Formula
- on multiplying both c and a by 4a, thus making
the denominators the same (Lesson 23), -
-
-
- This is the quadratic formula.
101Discriminant
- The radicand b² - 4ac is called the
discriminant. If the discriminant is - a) PositiveThe roots are real and conjugate.
- b) Negative The roots are complex and
conjugate. - c) ZeroThe roots are rational and equal --
i.e. a double root.
102Factoring
- Problem 2. Find the roots of each quadratic by
factoring. - a) x² - 3x 2 b) x² 7x 12
- (x - 1)(x - 2) (x 3)(x 4)
- x 1 or 2. x -3 or -4.
103In the next slides you will reviewFunctions D.
Quadratic functions explain everything we know
about how to graph a parabola
104Functions
- A function is an operation on numbers of some set
(domain) that gives (calculates) one number for
every number from the domain. For example,
function 3x is defined for all numbers and its
result is a number multiplied by 3. The notation
is yf(x). x is called the argument of the
function, and y is the value of the function. The
inverse function of f(x), is a different function
of y that finds x that gives f(x) y.
105Functions
- We have seen that a function is a special
relation. In the same sense, real function is a
special function. The special about real function
is that its domain and range are subsets of real
numbers R. In mathematics, we deal with
functions all the time but with a difference.
We drop the formal notation, which involves its
name, specifications of domain and co-domain,
direction of relation etc. Rather, we work with
the rule alone. For example, - f(x) x22x3
- This simplification is based on the fact that
domain, co-domain and range are subsets of real
numbers. In case, these sets have some specific
intervals other than R itself, then we mention
the same with a semicolon () or a comma(,) or
with a combination of them - f(x) \?(x1) 2-1xlt-2,x0
- Note that the interval xlt-2,x0 specifies a
subset of real number and defines the domain of
function. In general, co-domain of real function
is R. In some cases, we specify domain, which
involves exclusion of certain value(s), like - f(x)
- 11-x,x?1
- This means that domain of the function is R-1 .
Further, we use a variety of ways to denote a
subset of real numbers for domain and range. Some
of the examples are - xgt1 denotes subset of real number greater than
1. - R-0,1 denotes subset of real number that
excludes integers 0 and 1. - 1ltxlt2 denotes subset of real number between 1
and 2 excluding end points. - (1,2 denotes subset of real number between 1
and 2 excluding end point 1, but including
end point 2. - Further, we may emphasize the meaning of
following inequalities of real numbers as the
same will be used frequently for denoting
important segment of real number line - Positive number means x gt 0 (excludes 0).
- Negative number means x lt 0 (excludes 0).
- Non - negative number means x 0 (includes 0).
- Non positive number means x 0 (includes 0).
106Quadratic Functions
- A quadratic function is one of the form f(x)
ax2 bx c, where a, b, and c are numbers with
a not equal to zero. - The graph of a quadratic function is a curve
called a parabola. Parabolas may open upward or
downward and vary in "width" or "steepness", but
they all have the same basic "U" shape. All
parabolas are symmetric with respect to a line
called the axis of symmetry. A parabola
intersects its axis of symmetry at a point called
the vertex of the parabola. - You know that two points determine a line. This
means that if you are given any two points in the
plane, then there is one and only one line that
contains both points. A similar statement can be
made about points and quadratic functions. - Given three points in the plane that have
different first coordinates and do not lie on a
line, there is exactly one quadratic function f
whose graph contains all three points. To graph
simplify (see quadratic equations) and plot the
points.
107Simplifying expressions with exponents
108Simplifying Exponents
- Use the Power of a Power Property, the Product of
a Power Property, the Quotient of a Power
Property, the Power of a Quotient Property, the
109Simplifying exponents
Use These
110Simplifying Exponents
111Simplifying expressions with radicals
112Simplifying radicals
- When presented with a problem like , we
dont have too much difficulty saying that the
answer 2 (since 2x24 ). Our trouble usually
occurs when we either cant easily see the answer
or if the number under our radical sign is not a
perfect square or a perfect cube. A problem
like may look difficult because there
are no two numbers that multiply together to give
24. However, the problem can be simplified. So
even though 24 is not a perfect square, it can be
broken down into smaller pieces where one of
those pieces might be perfect square. So now we
have - Simplifying a radical expression can also involve
variables as well as numbers. Just as you were
able to break down a number into its smaller
pieces, you can do the same with variables. When
the radical is a square root, you should try to
have terms raised to an even power (2, 4, 6, 8,
etc). When the radical is a cube root, you should
try to have terms raised to a power of three (3,
6, 9, 12, etc.). For example,
http//www.algebralab.org/lessons/lesson.aspx?file
Algebra_radical_simplify.xml
113Simplifying Radicals
- Use the root of a power, power of a root, product
of a root, and quotient of a root properties to
solve.
114In the next slides you will reviewMinimum of
four word problems of various types. You can mix
these in among the topics above or put them all
together in one section. (Think what types you
expect to see on your final exam.)
115Suppose that it takes Janet 6 hours to paint her
room if she works alone and it takes Carol 4
hours to paint the same room if she works alone.
How long will it take them to paint the room if
they work together?
Click to see answer.
- First, we will let x be the amount of time it
takes to paint the room (in hours) if the two
work together. -
- Janet would need 6 hours if she did the entire
job by herself, so her working rate is of
the job in an hour. Likewise, Carols rate is
of the job in an hour. -
- In x hours, Janet paints of the room
and Carol paints of the room. Since the
two females will be working together, we will add
the two parts together. The sum equals one
complete job and gives us the following equation
-
-
116Continued answer
- Multiply each term of the equation by the common
denominator 12
Simplify
Collect like terms
Solve for x
117Suppose Kirk has taken three tests and made 88,
90, and 84. Kirks teacher tells the class that
each test counts the same amount. Kirk wants to
know what he needs to make on the fourth test to
have an overall average of 90 so he can make an A
in the class.
Steps
118Suppose a bank is offering its customers 3
interest on savings accounts. If a customer
deposits 1500 in the account, how much interest
does the customer earn in 5 years?
- I is the amount of interest the account earns.
- P is the principle or the amount of money that is
originally put into an account. - r is the interest rate and must ALWAYS be in a
decimal form rather than a percent. - t is the amount of time the money is in the
account earning interest. -
If we want to find out the total amount in the
account, we would need to add the interest to the
original amount. In this case, there would be
1725 in the account
119The Smiths have a rectangular pool that measure
12 feet by 20 feet. They are building a walkway
around it of uniform width.
- The length of the larger rectangle is
, which simplifies to -
- Length larger rectangle
-
- The width of the larger rectangle is
, which simplifies to -
- Width larger rectangle
-
- The area for the larger rectangle then becomes
-
- Area larger rectangle
-
- The pool itself has an area of
square feet
120Answer continued
- Rearrange the terms for easier multiplication and
find the sum of 68 and 240. - Multiply the binomials.
- Combine like terms and subtract 308 from each
side. - Factor.
- Solve each factor.
- Since dimensions of a pool and a walkway around a
pool cannot be negativeour answer is that the
width of the walkway is 1 foot.
121Line of Best Fit or Regression Line
122Line of best fit
- A line of best fit is a straight line that best
represents the data on a scatter plot. This
line may pass through some of the points, none of
the points, or all of the points.
123Line of Best Fit
- You can find the line of best fit by estimation
or by using graphing calculators. - The line of best fit is good for estimating the
average of the points on the graph.
124Line of best fit (how to solve)
- 1. Separate the data into three groups of equal
size according to the values of the - horizontal coordinate.
- 2. Find the summary point for each group based on
the median x-value and the - median y-value.
- 3. Find the equation of the line (Line L) through
the summary points of the outer - groups.
- 4. Slide L one-third of the way to the middle
summary point. - a. Find the y-coordinate of the point on L with
the same x-coordinate as the - middle summary point.
- b. Find the vertical distance between the middle
summary point and the line by - subtracting y-values.
- c. Find the coordinates of the point P one-third
of the way from the line L to the - middle summary point.
- 5. Find the equation of the line through the
point P that is parallel to line L.
125Line of Best Fit
- Try to find the line of best fit for the points
(3,9)(4,8)(6,6)(7,5)(9,7)(11,9)(13,12)(14,17)(13,1
9).