Simplify - Help I am supposed to simplify this:
$$(x^2-1)^2 (x^3+1) (3x^2) + (x^3+1)^2 (x^2-1) (2x)$$
The answer is supposed to be this, but I can not seem to get to it:
$$x(x^2-1)(x^3+1)(5x^3-3x+2)$$
Thanks

$$(x^2-1)^2 (x^3+1) (3x^2) + (x^3+1)^2 (x^2-1) (2x)$$
Factor out the $(x^2-1)$ term to get
$$(x^2-1)\left((x^2-1) (x^3+1) (3x^2) + (x^3+1)^2(2x)\right)$$
then factor out the $(x^3+1)$ term to get
$$(x^2-1)(x^3+1)\left((x^2-1) (3x^2) + (x^3+1)(2x)\right)$$
then factor out the $x$ term to get
$$x(x^2-1)(x^3+1)\left((x^2-1) (3x) + (x^3+1)(2)\right)=x(x^2-1)(x^3+1)(5x^3-3x+2)$$
