1. Wed 2/24 Lesson 8 – 1 Learning Objective: To find direct, inverse, & joint variations Hw: Lesson 8 – 1 & 2 – 2 WS

2. Algebra II

3.  To find direct variation  To find inverse variation  To find joint variation

5. 1. Suppose y varies directly with x, and y = 9 when x = -15. Find y when x = 21. -15y = 9(21) -15y = 189 y = -12.6

6. 2. Suppose y varies directly with x. (3, 15)(x, 60) 15x = 3(60) 15x = 180 x = 12 Write a function. y = kx 15 = k(3) k =5

7. 3. Suppose y varies inversely with x, and x = 4 when y = 12. Find x when y = 3 4(12) = 3(x) 48 = 3x x = 16

8. 4. Suppose y varies inversely with x. (3, 7). Find constant of variation

9. 5. x y 215 47.5 103 152 = 30 k = 30

10. 6. x y 12 36 48

11. 7. x y 14 28 311 NOT DIRECT “k” is not constant So NEITHER

12. 8. z varies directly with the square of x and inversely with y. When x = 2, y = 4, z = 3. Find x when y = 6 and z = 2

14. 9. z varies jointly with x and y. x = 7, y = 2, z = 28. Find z when x = 6 and y = 4

15.  z varies directly with the square root of x and inversely with the square of y.  When x = 9, y = 2 and z = 8  Find y when x = 16 and z = 6