Whitney

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Systems of Equations

by, Whitney Aimee
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Substitution
Substitution is a method that is used to find the
values of the x and y variables in order to graph
them.
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Example
Problem Steps

• Set one of the equations equal to y.
• Plug the y into the second equation.
• Solve for x.

y 3x 8 y 4 x (4- x) 3x 8 48 x
3x 12 2x x 6
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Example (continued)
Problem
4. Plug the x into the first equation and solve
for y.
y 3(6) 8 y18-8 y10 6,10
Be sure to put the solution in solution sets.
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WHY...
Is it important?
Knowing how to use systems of equations is
important because it is used to organize data in
order to solve problems. Also, it is used often
in geometry to make problems simpler to solve.
For example, the solution sets make it easier to
graph. x,y
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Occupations
Systems of equations are used today in many
different professions such as
An accountant!
A scientist!
A mathematician!
An Algebra teacher! (They teach it not use it)?
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Real Life Example
If New Yorks population (18.2mil.) grows at a
constant rate of 0.02 million people per year and
Floridas population (14mil.) grows at a constant
rate of 0.26 million people per year, when would
Florida catch up to New York in population? What
would their population be then?
P 18.2 0.02t P 14 0.26t T 17.5 P
18.55 17.5, 18.55
2 main equations
Answer!
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Come back soon