If z varies jointly as the square of x and y, z = 24 when x = 2 and y = 3, find the

value of z when x = 4 and y = 8.

1 answer

reading it as it was typed, interpreting "and" as addition
"z varies jointly as the square of x and y"
---> z = k(x+y)^2
when z = 24, x = 2, y = 3
24 = k(2+3)^2
24 = 25k
k = 24/25

z = (24/25)(x+y)

plug in your given values