Answer by CubeyThePenguin(3113) (Show Source): You can put this solution on YOUR website!
x = 5y
xy = 320
Substitute the first equation into the second equation
(5y)(y) = 320
5y^2 = 320
y^2 = 64
y = 8 (y must be positive)
The integers are (x, y) = (40, 8).