Factor.
(x-4)^3 + (x+4)^3
I need help on this question, i have a test tommorow, thanks in advance!
You multiplied it out wrong. You can use the second formula you have, if you want, but it seems easier to multiply it out:
$\displaystyle (x-4)^3 = (x-4)(x-4)(x-4) = x^3-12x^2+48x-64$
$\displaystyle (x+4)^3 = (x+4)(x+4)(x+4) = x^3 + 12x^2 + 48x + 64$
Add them together and you get the two terms I was talking about: $\displaystyle 2x^3+96x$