2 x - x - 5
x^2 - x - 5
2 -5 + x - x
-5 + x^2 - x
/ ____\ / ____\ | 1 \/ 21 | | 1 \/ 21 | |x + - - + ------|*|x + - - - ------| \ 2 2 / \ 2 2 /
(x - 1/2 + sqrt(21)/2)*(x - 1/2 - sqrt(21)/2)
-5.0 + x^2 - x
-5 + x*(-1 + x)