2 x - 10*x - 21 -------------- 2 x - 9*x + 14
(-21.0 + x^2 - 10.0*x)/(14.0 + x^2 - 9.0*x)
-21 + x*(-10 + x) ----------------- 14 + x*(-9 + x)
2 -21 + x - 10*x ----------------- (-7 + x)*(-2 + x)
35 + x 1 - ------------- 2 14 + x - 9*x