Bezout’s Theorem and the Fundamental Theorem of Arithmetic
1. Let a, b, c ∈ Z. Prove that c = ma + nb for some m, n ∈ Z if
and only if gcd(a, b)|c.
2. Prove that if c|ab and gcd(a, c) = 1, then c|b.
3. Prove that for all a, b ∈ Z not both zero, gcd(a, b) = 1 if
and only if a and b have no prime factors in common.