2 x + x - 1
x^2 + x - 1
2 -1 + x + x
-1 + x + x^2
/ ___\ / ___\ | 1 \/ 5 | | 1 \/ 5 | |x + - - -----|*|x + - + -----| \ 2 2 / \ 2 2 /
(x + 1/2 - sqrt(5)/2)*(x + 1/2 + sqrt(5)/2)
-1.0 + x + x^2
-1 + x*(1 + x)