I need some help here. I'm not sure how to even begin. I've been trying to use different forms of the implication, but the contrapositive has me working with a not equal sign and I don't know how to prove something using an inequality; the contradiction has me working with the assumption, which I don't know how to take apart. I'm not asking for a full proof, just a nod in the right direction would suffice.Let a and b be integers. Assume 3|(a² + b²). Prove 3|a and 3|b.