main idea/vocabulary slope-intercept form y-intercept graph linear equations using the slope and...

• slope-intercept form

• y-intercept

• Graph linear equations using the slope and y-intercept.

BrainPop: Slope and Intercept

Find Slopes and y-intercepts of Graphs

Write the equation in the form y = mx + b.

Answer:

State the slope and the y-intercept of the graph of

the equation .

1. A

2. B

3. C

4. D0% 0%0%0%

State the slope and the y-intercept of the graph of

the equation

A.

B.

C.

D.

Find Slopes and y-intercepts of Graphs

State the slope and the y-intercept of the graph of the equation 2x + y = 8.

Write the original equation.

Answer: The slope of the graph is –2 and the y-intercept is 8.

Subtract 2x from each side.

Simplify.

y = –2x + 8 Write the equation in the form y = mx + b.

y = mx + b

=

1. A

2. B

3. C

4. D0% 0%0%0%

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.

D.

Graph Using Slope-Intercept Form

Step 1 Find the slope and y-intercept.

Step 2 Graph the y-intercept (0, 2).

Graph using the slope and y-intercept.

Graph Using Slope-Intercept Form

Step 3 Use the slope to locate a second point on the line.

Step 4 Draw a line through the two points.

Answer: change in y: up 2 units

change in x: right 3 units

1. A

2. B

3. C

4. D

0% 0%0%0%

Graph using the slope and y-intercept.

A. B.

C. D.

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

y = 3x + 4

First, find the slope and the y-intercept.

Answer:

Graph an Equation to Solve Problems

slope = 3

y-intercept = 4

Plot the point (0, 4).

Then locate another point up 3 and right 1.

Draw the line.

1. A

2. B

3. C

4. D0% 0%0%0%

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.

A. B.

C. D.

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.

1. A

2. B

0%0%

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.

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.

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.

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.

Graph an Equation to Solve a Problem

1. A

2. B

3. C

4. D

0% 0%0%0%

A. 1 day B. 2 days

C. 3 days D. 4 days

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.

1. A

2. B

3. C

4. D0% 0%0%0%

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?

(over Lesson 9-5)

A.

B.

C.

D.

1. A

2. B

3. C

4. D

0% 0%0%0%

(over Lesson 9-5)

A. $152 B. $168

C. $192 D. $210

Refer to the graph. Continuing at the rate shown, how much will Aisha have earned after working 21 hours?

1. A

2. B

3. C

4. D0% 0%0%0%

(over Lesson 9-5)

Determine whether the linear function is a direct variation. If so, state the constant of variation.

A. no B. yes; 2

C. D.

1. A

2. B

3. C

4. D0% 0%0%0%

(over Lesson 9-5)

A. $4.75

B. $6.80

C. $7.40

D. $8.50

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?