1. Direct, Inverse & Joint Variation

2. Direct Variation The variables x & y vary directly: Direct  Divide BIGGER

3. Direct Variation The variables x & y vary directly. Write an equation that relates x and y if x = 6 when y = 8. Then find x when y = 12.

4. Inverse Variation The variables x & y vary inversely: Inverse  Multiply BIGGER SMALLER

5. Direct Variation The variables x & y vary inversely. Write an equation that relates x and y if x = 3 when y = 12. Then find y when x = 9.

6. Determine whether x and y show direct variation, inverse variation, or neither. xy 232 416 88 4 DirectInverse

7. Determine whether x and y show direct variation, inverse variation, or neither. xy 132 203 294 345 DirectInverse

8. Determine whether x and y show direct variation, inverse variation, or neither. xy 27 49 87 109 DirectInverse NEITHER

9. Joint Variation The variable x varies jointly with y and z: directly

10. Joint Variation The variable z varies jointly with x & y. Write an equation that relates x, y, and z if x = 3, y = 7 and z = 8. Then find z when x = 9 and y = 4.

11. Write an equation for the relationship: y varies directly with x and inversely with z.

12. Write an equation for the relationship: a varies inversely with b and jointly with c and d.

13. Write an equation for the relationship: a varies directly with b and jointly with c and d.