argh this isn't a polynomial my bad, I think I should look in the previous chapters notes because I forgot all about these. :s

Hey, I came across an odd problem in factoring polynomials on my hw today. I don't remember covering it in class, and when checking the answer in the back of my book, I was wrong, but I'm not sure how, exactly...

problem:

m^4-256

my answer:

(m^2-16)(m^2+16)

books answer:

(m^2+16)(m+4)(m-4)

I don't see how my answer is wrong...if anybody could tell me why it's wrong, I would appreciate the help.