1/x + 1/(x + 2) = 8/15
The common denominator is 15x(x + 2). Once we find it, we don't need it and we just use the resulting numerators.
15(x + 2) + 15x = 8x(x + 2)
15x + 30 + 15x = 8x2 + 16x
8x2 - 14x - 30 = 0
4x2 - 7x - 15 = 0
(4x + 5)(x - 3) = 0
4x + 5 = 0
4x = -5
x = -5/4, not an integer
x - 3 = 0
x = 3
3 and 5 are your integers.