7 18 - - 3 + 1 - -- - 6*x + 9 x 2 x
18 7 7 - -- - 6*x + - 2 x x
7.0 + 7.0/x - 6.0*x - 18.0/x^2
4 3 2 -18*x - 6*x + 9*x + x *(7 - 2*x) ---------------------------------- 3 x
3 2 -18 - 6*x + 9*x + x*(7 - 2*x) ------------------------------- 2 x
7 18 7 + - - 6*x - -- x 2 x
/ 2 3\ -\18 - 7*x - 7*x + 6*x / -------------------------- 2 x
-18 + 7*x 7 - 6*x + --------- 2 x