Alright, so I have $x^3 + 2x^2y - 4x - 8y$. I've learned that I need to group them together, so I chose to group $2x^2y - 4x$ and $x^3 - 8y$
When taking out their GCF, the numbers left in the parenthesis didn't match up, in fact, I couldn't find the GCF of anything for the second group.
So there is either a solution or it is prime, according to my algebra teacher, however, I'm not sure how to tell if something is prime or not. Can someone please help me?
EDIT: Could it also be that I am just grouping them incorrectly?
SECOND EDIT: Alright, I regrouped them a different way, into (-4x + x^3) + (2x^2y - 8y). After factoring them out, I came up with x(-4 + x^2) + 2y(x^2 - 4). The terms in the parenthesis are the same, but they are flipped. Does this mean that my answer is incorrect?