Question

The variable z varies jointly with x and y. Also, z = -75 when x = 3 and y = -5. What equation describes this variation? What is the constant of variation? k =

Answer 1

Answer:

z = 5xy

Step-by-step explanation:

since z varies jointly with x and y then

z = kxy ← k is the constant of variation

to find k use the given condition z = - 75 when x = 3 and y = - 5

k = $\frac{z}{xy}$ = $\frac{-75}{-15}$ = 5 and

z = 5xy ← equation of variation

Answer 2

Answer: z=kxy, k=5, z=-10

Step-by-step explanation: hope that helps