`(ax)/b-(by)/a=a+b`
`ax-by=2ab-(1)`
`a^2x-b^2y=a^2b+ab^2-(2)`
from equation 1 and 2
`y=(a^2b-ab^2)/(b^2-ab)`
`=(b(a^2-ab))/(b(b-a))`
`=(-a(a-b))/(b-a)`
`y=-a`
`ax-by=2ab`
`ax+ab=2ab`
`ax=ab`
`x=b`.