(adsbygoogle = window.adsbygoogle || []).push({}); 1. The problem statement, all variables and given/known data

If n>4 is a composite number, show that n|(n-1)! Conclude that (n-1)! not congruent -1(mod n).

(This shows that Wilson's theorem can be used as a proof of primality. It is unfortunately not practical for large numbers)

2. Relevant equations

3. The attempt at a solution

I know in words why a composite (ab) number does not work, but am not really sure how to prove it. Can anyone give me a jumping off point for this problem please?

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# Homework Help: Intro to number theory congruence problem 1

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