1. Lesson 3­4.notebook September 30, 2013
Assignment:
1­­>L3.4, pg. 183­184, #10­27 (all) ­ Due Tomorrow (10/1)
2­­>Checkpoint 3.1­3.3 ­ Due Tomorrow (10/1)
3­­>Test signed??
4­­>Chapter 3 Test ­ Tuesday (10/8)

2. Lesson 3­4.notebook September 30, 2013
Lesson 3.4 WarmUp:
Graph #1­2 by finding the x­intercept and y­intercept:
1) 2x + 5y = 10
2) ­3x ­ 4y = 7
Graph by using an x/y table of values.
3) y = 3x ­ 6
4) y = ­2x + 3
5) y = 1/2x ­ 2

3. Lesson 3­4.notebook September 30, 2013
Lesson 3.4:
*direct variation ­ an equation in the form, y = kx, where k = 0
*constant of variation or constant of proportionality ­ the "k" in an
equation in the form, y = kx
***Same thing as the slope....
however, direct variation equations will always
go through the origin!

4. Lesson 3­4.notebook September 30, 2013
Lesson 3.4 examples:
Graph each equation.
A) y = ­4x
Y
X
constant of variation =
slope =

5. Lesson 3­4.notebook September 30, 2013
Y
X
B) y = 1/2x
constant of variation =
slope =

6. Lesson 3­4.notebook September 30, 2013
Suppose y varies directly as x. Write a direct variation equation that relates x and y.
Then solve.
C) If y = 72 and x = 8, find y when x = 10

7. Lesson 3­4.notebook September 30, 2013
D) If y = 14 and x = 98, find y when x = ­28