Hi MHF,

Usually I can factor, but this particular problem is just killing me today. I have been trying to figure this out for over an hour...

$\displaystyle 128r^3+686z^3$

I know two things...

I know I can immediatly factor out the 2 and take it down to $\displaystyle 2(64r^3+343z^3)$.

And I know the answer is going to be in the form of $\displaystyle 2(binomial)(trinomial).$

But for the life of me I cannot seem to find the proper middle terms to make it work.

Thanks in advance.