Transcript Slope-Intercept Form

• Graph linear equations using the slope and
y-intercept.
• slope-intercept form
• y-intercept
BrainPop:
Slope and Intercept
Find Slopes and y-intercepts of Graphs
State the slope and the y-intercept of the graph of
the equation
.
Write the equation in the
form y = mx + b.
Answer:
State the slope and the y-intercept of the graph of
the equation
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B.
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Find Slopes and y-intercepts of Graphs
State the slope and the y-intercept of the graph of
the equation 2x + y = 8.
=
y = –2x + 8
Write the original equation.
Subtract 2x from each side.
Simplify.
Write the equation in the form
y = mx + b.
y = mx + b
Answer: The slope of the graph is –2 and the
y-intercept is 8.
State the slope and the y-intercept of the graph of the
equation 3x + y = 5.
A. slope = –3; y-intercept = 5
B. slope = –3; y-intercept = –5
C.
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Graph Using Slope-Intercept Form
Graph
using the slope and y-intercept.
Step 1 Find the slope and y-intercept.
Step 2 Graph the y-intercept (0, 2).
Graph Using Slope-Intercept Form
Step 3 Use the slope to locate a second point on the
line.
change in y: up 2 units
Answer:
change in x: right 3 units
Step 4 Draw a line through the
two points.
using the slope and y-intercept.
D.
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Graph
Graph an Equation to Solve Problems
MOVIE RENTAL A movie rental store charges $4 to
rent a movie. If a movie is returned late, the charge
is $3 extra per day. The total cost is given by the
equation y = 3x + 4, where x is the number of days
the movie is late. Graph the equation.
Graph an Equation to Solve Problems
First, find the slope and the y-intercept.
y = 3x + 4
slope = 3
y-intercept = 4
Plot the point (0, 4).
Then locate another point
up 3 and right 1.
Draw the line.
Answer:
GAME RENTAL A game rental store charges $5 to rent a game.
If a game is returned late, the charge is $5 extra per day. The
total cost is given by the equation y = 5x + 5, where x is the
number of days the game is late. Graph the equation.
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Graph an Equation to Solve a Problem
MOVIE RENTAL A movie rental
store charges $4 to rent a
movie. If a movie is returned
late, the charge is $3 extra per
day. The total cost is given by
the equation y = 3x + 4 where x
is the number of days the
movie is late. Describe what
the slope and y-intercept of the
graph represent.
Answer: The slope 3 represents the rate of change in
price each day a movie is late. The y-intercept
4 is the minimum charge for renting a movie.
GAME RENTAL A game rental
store charges $5 to rent a game. If a
game is returned late, the charge is
$5 extra per day. The total cost is
given by the equation y = 5x + 5,
where x is the number of days the
game is late. Describe what the
slope and y-intercept of the graph
represent.
0%
A
B. The slope represents the rate of change in
price each day a game is late. The y-intercept
represents the maximum charge for renting a
game.
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2.
A
B
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B
A. The slope represents the rate of change in
price each day a game is late. The y-intercept
is the minimum charge for renting a game.
Graph an Equation to Solve a Problem
MOVIE RENTAL A movie rental
store charges $4 to rent a
movie. If a movie is returned
late, the charge is $3 extra per
day. The total cost is given by
the equation y = 3x + 4 where x
is the number of days the
movie is late. Is the total cost
proportional to the number of
days the movie is late? Explain.
Graph an Equation to Solve a Problem
Compare the ratio of total cost to
number of days late.
Answer: The total cost is not proportional to the number
of days late.
GAME RENTAL A game rental
store charges $5 to rent a game.
If a game is returned late, the
charge is $5 extra per day. The
total cost is given by the
equation y = 5x + 5, where x is
the number of days the game is
late. Use the graph to find how
many days late a game is if the
late charge is $10.
D. 4 days
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C. 3 days
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B. 2 days
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A. 1 day
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(over Lesson 9-5)
Refer to the graph. The amount of money Aisha
earns is directly proportional to the number of hours
she works at the bookstore. What is the ratio of
money earned to hours worked?
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B.
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(over Lesson 9-5)
Refer to the graph. Continuing at
the rate shown, how much will
Aisha have earned after working
21 hours?
A. $152
B. $168
C. $192
D. $210
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(over Lesson 9-5)
Determine whether the linear function is a direct
variation. If so, state the constant of variation.
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B. yes; 2
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A. no
(over Lesson 9-5)
At the farmer’s market, they are selling 10 ears of
corn for $4.00. How much would it cost to buy
17 ears of corn?
A. $4.75
B. $6.80
C. $7.40
D. $8.50
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