Let a and b be relatively prime integers. (a) Let b'b mod a. Prove that a and b' are relatively prime. (b) Suppose that alc and blc. Prove that (ab)|c. Let a and b be relatively prime integers. (a) Let b'b mod a. Prove that a and b' are relatively prime. (b) Suppose that alc and blc. Prove that (ab)|c