I have to factor these two problems but am having some difficulties

X^3y^6-64 & (x+y)^3+(x-y)^3

These are just the difference of 2 cubes.

a^3-b^3 = (a-b)(a^2+ab+b^2)

So, the first one is

x^3y^6-64
= (xy^2)^3 - 4^3
= (xy^2-4)((xy^2)^2+(xy^2)(4)+4^2)
= (xy^2-4)(x^2y^4+4xy^2+16)

Do the other in like wise. It comes out very simple.

You can use wolframalpha.com to check your answer.