# Homework Help: Factorising Problem

1. Jan 27, 2010

### rudders93

1. The problem statement, all variables and given/known data

It's a calculus problem. But I can get all that, it's just this final bit of factorising the answer that has me stumped. The answer I get is correct (as my calculator factorises it into the same answer as the book has), but I've been looking at it and I can't seem to figure out how to factorise it. So I was wondering if someone could please show the steps / techniques used to factorise this problem:

2. Relevant equations

Factorise $(32x^3(2x^2 + 1) + 8x(2x^2 + 1)^2)$

3. The attempt at a solution

I tried taking out 8x as the common factor to get to: $8x(4x^2(2x^2 + 1) + (2x^2 + 1)^2))$ but I still can't see any way to further simplify it.

The answer by the way (according to my calculator / book) is: $8 x (2 x^2+1) (6 x^2+1)$

Thanks!

2. Jan 27, 2010

### Staff: Mentor

You can take out 8x(2x2 + 1) from each term. What do you have left?

3. Jan 27, 2010

### rudders93

Ah. Gotcha. Thanks!!!

4. Jan 28, 2010

### Tevion

8 x (2 x^2+1) (6 x^2+1)