12. Let m € Z. Prove that if m is not a multiple of 5, then either m² = 1 (mod 5), or m² = -1 (mod 5). 13. Let a, b E Z.
Posted: Tue Jul 12, 2022 12:44 pm
12. Let m € Z. Prove that if m is not a multiple of 5, then either m² = 1 (mod 5), or m² = -1 (mod 5). 13. Let a, b E Z. Prove that if ax + by : = 1 for some x, y ≤ Z, then gcd(a, b) = 1.