I don't know how to expand... much less this equation.. I reaalllyy need helpASAP! PLEASE?

Do you mean:

(x+6)^3

or

(x-6)^3?

You can make it like this:

(x+6)^3 = (x+6)(x+6)^2

You expand the quadratic and continue the expansion when you're done.

Of, you could use the binomial theorem;

(a + b)^n = a^n + ^nC_1(a)^{n-1}(b)^1 + ^nC_2(a)^{n-2}(b)^2 + ... + ^nC_r(a)^{n-r}(b)^r + b^n