3 x - 4*x
x^3 - 4*x
/ 2\ x*\-4 + x /
x*(-4 + x^2)
(x + 2)*x*(x - 2)
((x + 2)*x)*(x - 2)
x^3 - 4.0*x
x*(-2 + x)*(2 + x)