So I needed to factor -4x5-8x4+8x3+4x. I factored out a -4x and I am left with x4+2x3-2x2-4. The problem is I am unsure how to factor x4+2x3-2x2-4. I know how to long divide polynomials but I have not done synthetic division in over 4 years. From what I have seen on the internet it seems like a lot of guess and check.