Factor.
(x-4)^3 + (x+4)^3

I need help on this question, i have a test tommorow, thanks in advance!

2. ## Re: Advanced Functions HELP!!!

Multiply it out. Then, you will have two terms, one will have an $\displaystyle x^3$ and one will have an $\displaystyle x$. You will be able to factor out 2x.

3. ## Re: Advanced Functions HELP!!!

thanks for the reply, but when i multiply it out i get x^3-64+x^3+64. What do you mean by two terms?

4. ## Re: Advanced Functions HELP!!!

I was wondering if we are supposed to use the formulas :
x^3 - y^3 = (x-y)(x^2 + xy + y^2)
x^3 + y^3 = (x+y)(x^2 - xy + y^2)

5. ## Re: Advanced Functions HELP!!!

Originally Posted by SupremeAce
thanks for the reply, but when i multiply it out i get x^3-64+x^3+64. What do you mean by two terms?
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: $\displaystyle 2x^3+96x$