z is jointly proportional to x^2 and y^2. If z=264 when x=2 and y=4, find z when x=5 and y=3

Answer 1

z = kx²y²

Since z = 264 when x = 2 and y = 4, 264 = 64k

So, k = 264/64 = 4.125

z = 4.125x²y²

^{When x = 5 and y = 3, z = 4.125(25)(9) = 928.125}