2 - x + 2*x + 8
-x^2 + 2*x + 8
(x + 2)*(x - 4)
2 8 - x + 2*x
8 - x^2 + 2*x
8.0 - x^2 + 2.0*x
8 + x*(2 - x)
-(-4 + x)*(2 + x)