5. (a) Prove That An Integer N > 1 Is Prime If And Only If (n − 2)! = 1 (mod N). (b) If N Is A Composite Integer, Show That (n − 1)! = 0 (mod N), Except When N = 4. 6. Given A Prime Number P, Establish The Congruence
5. (a) Prove that an integer n > 1 is prime if and only if (n − 2)! = 1 (mod n). (b) If n is a composite integer, show that (n − 1)! = 0 (mod n), except when n = 4. 6. Given a prime number p, establish the congruence
