So since we know what x is, we can substitute it into the original equation for x like so to solve for y...
(2y - 8) + 5y - 10 = 0
2y - 8 + 5y = 10
2y + 5y = 18
7y = 18
y = 18/7 (or about 2.57)
So now we know what x is, we can sub it into the below equation to solve for x...
x = 2(18/7) - 8
x = 36/14 - 8 (or about -5.43)