It is easy to show that for all odd x that:(adsbygoogle = window.adsbygoogle || []).push({});

(x^n-2) = 7 (mod 8)

but why are the factors of above either congruent 1 or 7 modula 8, i.e

factor(x^n-2) = {1,7} (mod 8)

can anyone give me a hint.

regards

Anton

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# Congruences of (x^n-2) and its factors

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