a*b + 5*b + 10 + 2*a -------------------- 2 a - 25
10 + 2*a + 5*b + a*b -------------------- 2 -25 + a
(10.0 + 2.0*a + 5.0*b + a*b)/(-25.0 + a^2)
10 + 2*a + b*(5 + a) -------------------- 2 -25 + a
2 + b ------ -5 + a