2 x *x*y ------- x*y - x
((x^2*x)*y)/(x*y - x)
2 y*x ------ -1 + y
y*x^2/(-1 + y)
3 y*x -------- -x + x*y
y*x^3/(-x + x*y)
2 2 x x + ------ -1 + y
x^2 + x^2/(-1 + y)