Answer:
x + y = 9.
Explanation:
xy = 2(x + y)
xy = 6(x - y)
2x + 2y = 6x - 6y
8y = 4x
x = 2y
Substitute for x in the first equation:
2y^2 = 2(2y + y)
2y^2 = 6y
y^2 = 3y
y(y - 3) = 0
y = 0, 3.
x = 2y = 0 , 6.
As the integers are positive they must be 3 and 6.
x + y = 3+6 = 9.