1. Advanced Math Topics Mrs. Mongold
Variation
Advanced Math Topics
Mrs. Mongold

2. Direct Variation
y varies directly as x if there is some nonzero constant k such that y = kx.
k is called the constant of variation

3. Example
If y varies directly as x and y = 12 when x = -3, find y when x = 16.
Find k first Then find y with given x
y = kx y = -4x
12 = k (-3) y = -4(16)
12 = -3k y = -64
k = -4

4. Joint Variation
y varies jointly as x and z if there is some nonzero constant k such that y = kxz

5. Example
Suppose y varies jointly as x and z. Find y when x = 8 and z = 3, if y = 16 when z = 2 and x = 5.
Find k first Then find y

6. Inverse Variation
y varies inversely as x if there is some nonzero constant k such that xy = k or y= k x

7. Example
If y varies inversely as x and y = 18 when x = -3, find y when x = -11
Find k First Then find y

8. Homework
Pg 428//1-18, Even, Even