2 x - 2*x + 1 ------------ x - 1
(x^2 - 2*x + 1)/(x - 1)
-1 + x
(1.0 + x^2 - 2.0*x)/(-1.0 + x)
2 1 + x - 2*x ------------ -1 + x
(1 + x^2 - 2*x)/(-1 + x)
1 + x*(-2 + x) -------------- -1 + x
(1 + x*(-2 + x))/(-1 + x)