1. 4 minutes
Warm-Up
Graph.
5x – 4y = 20
2) x = 5
3) y = -2

2. 5.1 Slope
Objectives:
To find the slope of a line given two points on the line
To describe slope for horizontal and vertical lines

3. Slope -4 -2 2 4 6 8 10 -6 -8
-10
Slope =
run
rise

4. Example 1
Graph the line containing points (2,1) and (7,6) and find the slope. -4 -2 2 4 6 8 10 -6 -8
-10
Slope =
run
rise

5. Practice Graph the line containing these points and find their slopes.
1) (-2,3) (3,5)
2) (0,-3) (-3,2)

6. Slope
Slope = or

7. Example 2
Find the slope of the line containing points (1,6) and (5,4).

8. Practice Find the slope of the lines containing these points.
1) (2,2) (8,9)
2) (-2,3) (2,1)
3) (5,-11) (-9,4)

9. Slope of a Horizontal Line
What about the slope of a horizontal line? -4 -2 2 4 6 8 10 -6 -8
-10
What is the rise?
What is the run? 6
Slope =
The slope of ANY horizontal line is 0.

10. Slope of a Vertical Line
What about the slope of a vertical line? -4 -2 2 4 6 8 10 -6 -8
-10
What is the rise? 5
What is the run?
Slope =
The slope of ANY vertical line is undefined.

11. Example 1 Find the slope of the line y = -4. Slope = -4 -2 2 4 6 8 10-6 -8
-10
Slope =

12. Example 2 Find the slope of the line x = 7. Slope =-4 -2 2 4 6 8 10 -6 -8
-10
Slope =
The line has no slope.

13. Practice
Find the slopes, if they exist, of the lines containing these points.
1) (9,7) (3,7)
2) (4,-6) (4,0)
3) (2,4) (-1,5)

14. 5 minutes
Warm-Up
Graph. Then find the slope.
y = 3x + 2
2) y = -2x +5

15. 5.2 Equations and Slope Objectives:
To find the slope and y-intercept of a line from an equation

16. Slope-Intercept Equation
Find the slope of the line y = 2x - 4. 8
y = 2x - 4 6 4 x y 2 -4 -8 -6 -4 -2 2 4 6 8 1 -2 -2
rise: -4 2 -4
run: -2 -6 -8
The y-intercept is -4.

17. Slope-Intercept Equation
y = mx + b
y = 4x + 8
slope
y = 2x - 3
y-intercept
slope
= 4
y-intercept
= 8
slope
= 2
y-intercept
= -3

18. Example 1 Find the slope and y-intercept of the line y = -4x + 4.
The slope is -4.
The y-intercept is 4.

19. Example 2 Find the slope and y-intercept of the line y = 5x - 7.
The slope is 5.
The y-intercept is -7.

20. Practice Find the slope and y-intercept of each line. y = x + 3

21. Example 3 Find the slope and y-intercept of the line 3x + 4y = 12.
solve for y
-3x x
4y = 12 – 3x 4 4
slope
y-intercept
= 3

22. Practice Find the slope and y-intercept of each line. y = -x - 3
2) 8x + 2y = 10
3) 3y – 6x = 12

23. Homework
p.326 #1-10,19-27 odds

24. Warm-Up 4 minutes Find the slope and y-intercept. y = 3x + 4
3) 2x + 7y = 9
4) 4x = 9y + 7

25. Example 1 Graph y = 3x + 2. What is the slope of this line?8
What is the slope of this line? 6 4 2 -8 -6 -4 -2 2 4 6 8 -2
What is the y-intercept? -4
b = 2 -6 -8

26. Example 2 Graph What is the slope of this line?8
What is the slope of this line? 6 4 2 -8 -6 -4 -2 2 4 6 8 -2
What is the y-intercept? -4
b = -3 -6 -8

27. Practice
Graph each line.
y = 3x - 5
2) y = -2x + 4 3)

28. Example 3 Graph 3x + 4y = 12. 3x + 4y = 12 solve for y -3x -3x

29. Example 3 Graph 3x + 4y = 12. slope y-intercept 8 6 4 2 -8 -6 -4 -2 2

30. Practice
Graph each line.
7x + 2y = 4
2) 5y – 10 = 4x