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 [itex](32x^3(2x^2 + 1) + 8x(2x^2 + 1)^2)[/itex] 3. The attempt at a solution I tried taking out 8x as the common factor to get to: [itex]8x(4x^2(2x^2 + 1) + (2x^2 + 1)^2))[/itex] but I still can't see any way to further simplify it. The answer by the way (according to my calculator / book) is: [itex]8 x (2 x^2+1) (6 x^2+1)[/itex] Thanks!