what does x4-256 equal

Question

I have no clue on what the answer is to this math question that I am currently stuck on in a study island post test.

Answer 1

x⁴-256

I assume it means to factor completely.

This is the difference of two squares.

x⁴-256=(x²-16)(x²+16)=(x-4)(x+4)(x²+16)