Alg 4.6
Notes
4.6 Direct Variation
Identify direct variation, constant of variation, and write and graph direct variation graphs
Graph the following with your partner
1. y = 5x -1
2. y = -2x
3. x – 3y = 0
What do the last two graphs have in common? ______________________________________________
Slope intercept form:
Direct variation equation:
Examples of Direct Variation Equations:
Examples of non-Direct Variation Equations:
Tell whether the equation represents direct variation. If so, identify the constant of variation.
4
1. 2 x  y  3
2. 4 x  5 y  0
3. y   x  1
4. 6 x  7 y
3
Graph the direct variation equations.
3
5. y  x
m= _______
4
b= _______
6. y   x
m= _______
b= _______
Given that y varies directly with x, use the specified values to write a direct variation equation that
relates x and y.
7. x = 4, y = 12
8. x = 3, y = 39
9. x = -18, y = -4
10. The graph of a direct variation equation is shown. Write the direct variation equation. Then
find the value of y when x = 8
REAL WORLD SCENARIOS:
A.
C.
B.
D.