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Old November 2nd, 2009, 06:00 PM
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Question Need help with a proof involving congruence and mod stuff

Prove that if a and b are integers and p is a prime, then (a+b)^p is congruent to a^(p)+b^(p) (mod p). Help please?
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Old November 2nd, 2009, 10:00 PM
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tonio is just really nicetonio is just really nicetonio is just really nicetonio is just really nicetonio is just really nice
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Originally Posted by steph3824 View Post
Prove that if a and b are integers and p is a prime, then (a+b)^p is congruent to a^(p)+b^(p) (mod p). Help please?

(a+b)^p=\sum\limits_{k=0}^p\binom{p}{k}a^{p-k}b^k.

Well, now just prove that for 1\leq k\leq p-1\,,\,\,p\mid \binom{p}{k} and you're done

Tonio
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