2 x - 2*x - 4
x^2 - 2*x - 4
2 -4 + x - 2*x
-4 + x^2 - 2*x
/ ___\ / ___\ \x + -1 + \/ 5 /*\x + -1 - \/ 5 /
(x - 1 + sqrt(5))*(x - 1 - sqrt(5))
-4.0 + x^2 - 2.0*x
-4 + x*(-2 + x)