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

Show n^{4}- 1 is divisible by 5 when n is not divisible by 5.

2. Relevant equations

3. The attempt at a solution

My thought here is proof by cases, one case being where n is divisible by 5 and the other case saying n is not divisible by 5. I am just not totally sure how to implement this strategy.

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# Homework Help: Proof involving divisibilty

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