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How can you prove that:

$$a^7\equiv a\:(\text{mod } 42)$$

I haven't been given any other information other than to use Fermat's theorem.

  • 2
    "Use Fermat's theorem" is a pretty good hint. What are your thoughts on how to apply it?2012-11-27
  • 3
    Work separately modulo $7$, $2$, and $3$.2012-11-27

5 Answers 5