2 x + 4*x - 5
x^2 + 4*x - 5
2 -5 + x + 4*x
-5 + x^2 + 4*x
(x + 5)*(x - 1)
-5.0 + x^2 + 4.0*x
-5 + x*(4 + x)
(-1 + x)*(5 + x)