Algebra 1 Notes

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• Algebra 1 Notes
• Lesson 5-4Writing Equations in Slope-Intercept
  Form

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Objectives

• Write equations in slope intercept form given the
  slope and one point
• Write equations in slope intercept form given two
  point

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Example 1 Write an equation of a line that passes
through (2, -3) with slope ½. y mx b
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Example 1 Write an equation of a line that passes
through (2, -3) with slope ½. y mx b
y ½ x b

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Example 1 Write an equation of a line that passes
through (2, -3) with slope ½. y mx b
y ½ x b
-3 ½ (2) b
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Example 1 Write an equation of a line that passes
through (2, -3) with slope ½. y mx b
y ½ x b
-3 ½ (2) b -3 1
b
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Example 1 Write an equation of a line that passes
through (2, -3) with slope ½. y mx b
y ½ x b
-3 ½ (2) b -3 1
b -1 -1
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Example 1 Write an equation of a line that passes
through (2, -3) with slope ½. y mx b
y ½ x b
-3 ½ (2) b -3 1
b -1 -1 -4 b
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Example 1 Write an equation of a line that passes
through (2, -3) with slope ½. y mx b
y ½ x b
-3 ½ (2) b -3 1
b -1 -1 -4 b y ½ x 4
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Example 2 Write an equation of a line that passes
through (-3, -4) and (-2, -8). Slope
y-intercept
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Write equation given two intercepts

• x-int 2
• y-int -5

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Write equation given two intercepts

• x-int 2
• y-int -5
• Sketch Graph

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Write equation given two intercepts

• x-int 2
• y-int -5
• Sketch Graph
• m

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Write equation given two intercepts

• x-int 2
• y-int -5
• Sketch Graph
• m

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Write equation given two intercepts

• x-int 2
• y-int -5
• Sketch Graph
• m
• b

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Write equation given two intercepts

• x-int 2
• y-int -5
• Sketch Graph
• m
• b -5

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Write equation given two intercepts

• x-int 2
• y-int -5
• Sketch Graph
• m
• b -5
• y x - 5

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Homework Worksheet!
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Begin Day 2

• Slope Intercept Form Story Problem Walk Through

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Example 3 In the middle of the 1998 baseball
season, Mark McGwire seemed to be on track for
most runs batted in (RBI). After 40 games,
McGwire had 45 RBIs. After 86 games, he had 87
RBIs. Write an equation in slope intercept form
to estimate the number of runs batted in for any
number of games that year.
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Example 3 In the middle of the 1998 baseball
season, Mark McGwire seemed to be on track for
most runs batted in (RBI). After 40 games,
McGwire had 45 RBIs. After 86 games, he had 87
RBIs. Write an equation in slope intercept form
to estimate the number of runs batted in for any
number of games that year. Define Variables x
y
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Example 3 In the middle of the 1998 baseball
season, Mark McGwire seemed to be on track for
most runs batted in (RBI). After 40 games,
McGwire had 45 RBIs. After 86 games, he had 87
RBIs. Write an equation in slope intercept form
to estimate the number of runs batted in for any
number of games that year. Define Variables x
games y runs batted in
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Example 3 In the middle of the 1998 baseball
season, Mark McGwire seemed to be on track for
most runs batted in (RBI). After 40 games,
McGwire had 45 RBIs. After 86 games, he had 87
RBIs. Write an equation in slope intercept form
to estimate the number of runs batted in for any
number of games that year. Define Variables 2
points, slope, or y-int x games y runs batted
in
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Example 3 In the middle of the 1998 baseball
season, Mark McGwire seemed to be on track for
most runs batted in (RBI). After 40 games,
McGwire had 45 RBIs. After 86 games, he had 87
RBIs. Write an equation in slope intercept form
to estimate the number of runs batted in for any
number of games that year. Define Variables 2
points, slope, or y-int x games (40,45) y
runs batted in (86, 87)
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Example 3 Define Variables 2 points, slope, or
y-int x games (40,45) y runs batted
in (86, 87) Find slope and y-int m
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Example 3 Define Variables 2 points, slope, or
y-int x games (40,45) y runs batted
in (86, 87) Find slope and y-int m
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Example 3 Define Variables 2 points, slope, or
y-int x games (40,45) y runs batted
in (86, 87) Find slope and y-int m 0.91
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Example 3 Define Variables 2 points, slope, or
y-int x games (40,45) y runs batted
in (86, 87) Find slope and y-int m 0.91
y 0.91x b
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Example 3 Define Variables 2 points, slope, or
y-int x games (40,45) y runs batted
in (86, 87) Find slope and y-int m 0.91
y 0.91x b 45 0.91(40) b
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Example 3 Define Variables 2 points, slope, or
y-int x games (40,45) y runs batted
in (86, 87) Find slope and y-int m 0.91
y 0.91x b 45 0.91(40) b 45 36.4 b
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Example 3 Define Variables 2 points, slope, or
y-int x games (40,45) y runs batted
in (86, 87) Find slope and y-int m 0.91
y 0.91x b 45 0.91(40) b 45 36.4
b -36.4 -36.4
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Example 3 Define Variables 2 points, slope, or
y-int x games (40,45) y runs batted
in (86, 87) Find slope and y-int m 0.91
y 0.91x b 45 0.91(40) b 45 36.4
b -36.4 -36.4 8.6 b
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Example 3 Define Variables 2 points, slope, or
y-int x games (40,45) y runs batted
in (86, 87) Find slope and y-int Write the
equation m 0.91 y 0.91x b 45
0.91(40) b 45 36.4 b -36.4 -36.4 8.6 b
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Example 3 Define Variables 2 points, slope, or
y-int x games (40,45) y runs batted
in (86, 87) Find slope and y-int Write the
equation m 0.91 y 0.91x 8.6 y 0.91x
b 45 0.91(40) b 45 36.4 b -36.4
-36.4 8.6 b
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Example 3 The record for RBIs in a season is 190.
Use your equation to decide if McGwire should
break the record since there were 162 games that
played that year. Plug in the information for the
correct variable
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Example 3 The record for RBIs in a season is 190.
Use your equation to decide if McGwire should
break the record since there were 162 games that
played that year. Plug in the information for the
correct variable y 0.91(162) 8.6
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Example 3 The record for RBIs in a season is 190.
Use your equation to decide if McGwire should
break the record since there were 162 games that
played that year. Plug in the information for the
correct variable y 0.91(162) 8.6 Solve for
RBIs
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Example 3 The record for RBIs in a season is 190.
Use your equation to decide if McGwire should
break the record since there were 162 games that
played that year. Plug in the information for the
correct variable y 0.91(162) 8.6 Solve for
RBIs Answer the question y 156.02
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Example 3 The record for RBIs in a season is 190.
Use your equation to decide if McGwire should
break the record since there were 162 games that
played that year. Plug in the information for the
correct variable y 0.91(162) 8.6 Solve for
RBIs Answer the question y 156.02 No, he
should only have 156 RBIs
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Example 3 In 2000, the cost of many items
increased because of the increase in the cost of
petroleum. In Chicago, a gallon of self-serve
regular gasoline cost 1.76 in May and 2.13 in
June. Write a linear equation to predict the cost
of gasoline in any month in 2000, using 1 to
represent January.
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Example 3 In 2000, the cost of many items
increased because of the increase in the cost of
petroleum. In Chicago, a gallon of self-serve
regular gasoline cost 1.76 in May and 2.13 in
June. Write a linear equation to predict the cost
of gasoline in any month in 2000, using 1 to
represent January. x y
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Example 3 In 2000, the cost of many items
increased because of the increase in the cost of
petroleum. In Chicago, a gallon of self-serve
regular gasoline cost 1.76 in May and 2.13 in
June. Write a linear equation to predict the cost
of gasoline in any month in 2000, using 1 to
represent January. x Month y price per gal.
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Example 3 May 1.76 June 2.13
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Example 3 May 1.76 (5, 1.76) June 2.13
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Example 3 May 1.76 (5, 1.76) June
2.13 (6, 2.13) Slope y-intercept
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Example 4 Use the equation
to predict the cost of a gallon of gasoline
in July. 2.50 per gallon
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Example 4 Use the equation
to predict the cost of a gallon of gasoline
in July. 2.50 per gallon x 3,000 gallons
7,500 in July
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Example 4 Use the equation
to predict the cost of a gallon of gasoline
in July. Do they need to add to the budget?
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Y
Example 4 Use the equation
to predict the cost of a gallon of gasoline
in July. Do they need to add to the budget? Yes,
they need to add 500.
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• Vocabulary
• Linear Extrapolation
• - Linear Interpolation

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Homework Pg 284 34 44 (all)