1. Bellwork
Find the x and y intercepts and then graph the line for the following equation: 2x + 6y = 12

2. 2x + 6y = 12 x - intercept Plug 0 in for y 2x + 6(0) = 12 2x = 12
y - intercept
Plug 0 in for x
2(0) + 6y = 12
6y = 12
y = 2

3. 2x + 6y = 12 Y X

4. To be able to find the slope of a line given two points on the line.
Today’s Objective
To be able to find the slope of a line given two points on the line.

5. Slope
Think of some activities or structures that involve the word slope.
Skiing, Stairway, etc..

6. Slope Slope means rise over run rise run
Slope is how much a line rises compared to how much it runs.

7. Notice the Stair Step effectY
Slope is how much a line rises compared to how much it runs X
This line rises 1 and runs -1

8. The Slope Formula
Any two points on a line can be labeled (x1,y1) and (x2,y2) then...

9. The Slope Formula
The formula is
y2 - y1 x2 - x1

10. Label the 2 Points
(-1,5)=(x1,y1) Y X
(2,2)=(x2,y2)

11. Let (-1,5) be (x1,y1) and (2,2) be (x2,y2) so…
Using the Formula
Let (-1,5) be (x1,y1) and (2,2) be (x2,y2) so…
2-5 = -3 = -1

12. So..The slope is -1 Y
Slope = -1 X

13. Notice the Stair Step effectY
Slope = -1 X

14. Positive and Negative Slopes
The slope of -1 means that the line rises -1(goes down) and runs 1(goes to the right).
Lines with negative slope go up to the left
Lines with positive slope go up to the right.

15. Horizontal and Vertical Lines
Horizontal lines have 0 Slope
Vertical lines have NO Slope

16. Horizontal Lines Y
Slope = 0 X

17. Vertical Lines Y
No Slope X

18. Classwork
Do worksheet 4.4
HomeWork
page 201 (9-28)