6 8 x - x
x^6 - x^8
(x + 1)*x*(x - 1)
((x + 1)*x)*(x - 1)
6 / 2\ x *\1 - x /
x^6*(1 - x^2)
6 -x *(1 + x)*(-1 + x)
-x^6*(1 + x)*(-1 + x)