1. Graph 3x + y = 6 by making a “T” Table and graphing the line.
Bellwork
Graph 3x + y = by making a “T” Table and graphing the line.

2. The “T” Table
X Y 1 2 -1

3. 3x + y = 6 ~ y = -3x + 6 y = -3x + 6 y = -3(1) + 6 y = -3 + 6 y = 3

4. 3x + y = 6 ~ y = -3x + 6 y = -3x + 6 y = -3(0) + 6 y = 0 + 6 y = 6

5. The “T” Table
X Y

6. Now DRAW the Line Y
(1,3)
(-1,9) X
(2,0)
(0,6)

7. Today’s Objective
To be able to find the x and y intercepts of an equation and use them to draw a quick graph.

8. The intercepts are where the line crosses the axis.
Y-Intercept = 6 Y
X-Intercept = 2 X

9. Finding the intercepts
3x + y = 6 To find the x-intercept, let y = 0
3x + (0) = 6
3x = 6
x = 2

10. Finding the intercepts
3x + y = 6 To find the y-intercept, let x = 0
3(0) + y = 6
y = 6

11. The graph of 3x + y = 6 Y
y-intercept = 6
x-intercept = 2 X

12. Compare the 2 graphs

13. Finding the intercepts
x + 5y = 10 To find the x-intercept, let y = 0
x + 5(0) = 10
x = 10

14. Finding the intercepts
x + 5y = 10 To find the y-intercept, let x = 0
0 + 5y = 10
5y = 10
y = 2

15. The graph of x + 5y = 10 Y
y-intercept = 2
x-intercept = 10 X

16. Find the intercepts and graph
3x + 4y = 12

17. Finding the x-intercept
3x + 4y = 12
3x + 4(0) = 12
3x + 0 = 12
3x = 12
x = 4

18. Finding the y-intercept
3x + 4y = 12
3(0) + 4y = 12
0 + 4y = 12
4y = 12
y = 3

19. The graph of 3x + 4y = 12 Y
y-intercept = 3
x-intercept = 4 X

20. Find the intercepts and graph
y = 4x - 4
You try this one.

21. Finding the x-intercept
y = 4x - 4
0 = 4x - 4
0 + 4 = 4x
4 = 4x
1 = x

22. Finding the y-intercept
y = 4x - 4
y = 4(0) - 4
y = -4

23. The graph of y = 4x - 4 Y
x-intercept = 1 X
y-intercept = -4

24. Classwork
Do worksheet 4.3
Homework
page193 ( even)