1. Ch. 8.5 Variation Functions

2. Direct Variation y varies directly as x
If y varies directly as x and y = 15 when x = – 5, find y when x = 7.
If r varies directly as t and r = –20 when t = 4, find r when t = –6.

3. Joint Variation y varies jointly as x and z
Suppose y varies jointly as x and z. Find y when x = 9 z= 2, if y = 20 when z = 3 and x = 5.
Suppose r varies jointly as v and t. Find r when v = 2 and t = 8, if r = 70 and t = 4.

4. Inverse Variation y varies inversely as x
If a varies inversely as b and a = 28 when b = –2, find a when b = –10.
If x varies inversely as y and x = 24 when y = 4, find x when y = 12.

5. Combined Variation y varies directly as x, y varies inversely as z
Suppose f varies directly as g, and f varies inversely as h. Find g when f = 18 and h = –3, if y = 24 when h = 2 and f = 6.
Suppose p varies directly as r, and p varies inversely as t. Find t when r = 10 and p = –5, if t = 20 when p=4 and r=2.

6. DIVING The height that a diver leaps above a diving board varies directly with the amount that the tip of the diving board dips below its normal level. If a diver leaps 44 inches above the diving board when the diving board tip dips 12 inches, how high will the diver leap above the diving board if the tip dips 18 inches?