1. BrainPop: Slope and Intercept
Graph linear equations using the slope and y-intercept.
slope-intercept form
y-intercept
BrainPop: Slope and Intercept
Main Idea/Vocabulary

2. 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:
Example 1

3. State the slope and the y-intercept of the graph of the equationB. C. D. A B C D
Example 1

4. 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. =
Subtract 2x from each side.
Simplify.
y = –2x + 8 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.
Example 2

5. A. slope = –3; y-intercept = 5 B. slope = –3; y-intercept = –5 C. D.
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. A B C D
Example 2

6. 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).
Example 3

7. Graph Using Slope-Intercept Form
Step 3 Use the slope to locate a second point on the line.
change in y: up 2 units
change in x: right 3 units
Answer:
Step 4 Draw a line through the two points.
Example 3

8. Graph using the slope and y-intercept.
A. B.
C. D. A B C D
Example 3

9. 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.
Example 4

10. Graph an Equation to Solve Problems
First, find the slope and the y-intercept.
y = 3x + 4
Answer:
slope = 3
y-intercept = 4
Plot the point (0, 4).
Then locate another point up 3 and right 1.
Draw the line.
Example 4

11. GAME RENTAL A game rental store charges $5 to rent a game
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. A B C D
Example 4

12. 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.
Example 5

13. GAME RENTAL A game rental store charges $5 to rent a game
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. A B
Example 5

14. 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.
Example 6

15. 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.
Example 6

16. GAME RENTAL A game rental store charges $5 to rent a game
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. A B C D
A. 1 day B. 2 days
C. 3 days D. 4 days
Example 6

17. (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? A. B. C. D. A B C D
Five Minute Check 1

18. (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 A B C D
Five Minute Check 2

19. (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. A B C D
Five Minute Check 3

20. (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 A B C D
Five Minute Check 4

21. End of Custom Shows