Prove that if $p$ is prime and $a^p+b^p = c^p$ then $a+b-c = 0 mod p$












0












$begingroup$


I'm working on the following Fermat little theorem exercise:




Prove that if $p$ is prime and $a^p+b^p = c^p$ then $a+b-c = 0 mod p$




Also I find a relation with Fermat last theorem which says that no three positive integers $a, b$, and $c$ satisfy the equation $a^n$ + $b^n$ $=$ $c^n$ for any integer value of $n$ greater than $2$.



So is there a solution or a way to solve the problem based on the last theorem? How should I go ahead on this exercise? Any hint or help will be really appreciated.










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  • $begingroup$
    Fermat's Last Theorem is a distraction here - it says, amongst other things, that there are no solutions to the original for $pgt 2$. A false statement implies anything, so the implication is then trivially true for $pgt 2$ and easy for $p=2$. But really the statement here is an early and elementary observation in the journey towards proving the last theorem.
    $endgroup$
    – Mark Bennet
    Jan 29 at 7:43
















0












$begingroup$


I'm working on the following Fermat little theorem exercise:




Prove that if $p$ is prime and $a^p+b^p = c^p$ then $a+b-c = 0 mod p$




Also I find a relation with Fermat last theorem which says that no three positive integers $a, b$, and $c$ satisfy the equation $a^n$ + $b^n$ $=$ $c^n$ for any integer value of $n$ greater than $2$.



So is there a solution or a way to solve the problem based on the last theorem? How should I go ahead on this exercise? Any hint or help will be really appreciated.










share|cite|improve this question









$endgroup$












  • $begingroup$
    Fermat's Last Theorem is a distraction here - it says, amongst other things, that there are no solutions to the original for $pgt 2$. A false statement implies anything, so the implication is then trivially true for $pgt 2$ and easy for $p=2$. But really the statement here is an early and elementary observation in the journey towards proving the last theorem.
    $endgroup$
    – Mark Bennet
    Jan 29 at 7:43














0












0








0


1



$begingroup$


I'm working on the following Fermat little theorem exercise:




Prove that if $p$ is prime and $a^p+b^p = c^p$ then $a+b-c = 0 mod p$




Also I find a relation with Fermat last theorem which says that no three positive integers $a, b$, and $c$ satisfy the equation $a^n$ + $b^n$ $=$ $c^n$ for any integer value of $n$ greater than $2$.



So is there a solution or a way to solve the problem based on the last theorem? How should I go ahead on this exercise? Any hint or help will be really appreciated.










share|cite|improve this question









$endgroup$




I'm working on the following Fermat little theorem exercise:




Prove that if $p$ is prime and $a^p+b^p = c^p$ then $a+b-c = 0 mod p$




Also I find a relation with Fermat last theorem which says that no three positive integers $a, b$, and $c$ satisfy the equation $a^n$ + $b^n$ $=$ $c^n$ for any integer value of $n$ greater than $2$.



So is there a solution or a way to solve the problem based on the last theorem? How should I go ahead on this exercise? Any hint or help will be really appreciated.







number-theory modular-arithmetic






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asked Jan 29 at 6:39









mrazmraz

44319




44319












  • $begingroup$
    Fermat's Last Theorem is a distraction here - it says, amongst other things, that there are no solutions to the original for $pgt 2$. A false statement implies anything, so the implication is then trivially true for $pgt 2$ and easy for $p=2$. But really the statement here is an early and elementary observation in the journey towards proving the last theorem.
    $endgroup$
    – Mark Bennet
    Jan 29 at 7:43


















  • $begingroup$
    Fermat's Last Theorem is a distraction here - it says, amongst other things, that there are no solutions to the original for $pgt 2$. A false statement implies anything, so the implication is then trivially true for $pgt 2$ and easy for $p=2$. But really the statement here is an early and elementary observation in the journey towards proving the last theorem.
    $endgroup$
    – Mark Bennet
    Jan 29 at 7:43
















$begingroup$
Fermat's Last Theorem is a distraction here - it says, amongst other things, that there are no solutions to the original for $pgt 2$. A false statement implies anything, so the implication is then trivially true for $pgt 2$ and easy for $p=2$. But really the statement here is an early and elementary observation in the journey towards proving the last theorem.
$endgroup$
– Mark Bennet
Jan 29 at 7:43




$begingroup$
Fermat's Last Theorem is a distraction here - it says, amongst other things, that there are no solutions to the original for $pgt 2$. A false statement implies anything, so the implication is then trivially true for $pgt 2$ and easy for $p=2$. But really the statement here is an early and elementary observation in the journey towards proving the last theorem.
$endgroup$
– Mark Bennet
Jan 29 at 7:43










2 Answers
2






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5












$begingroup$

Write $$a^p+b^p-c^p=(a^p-a)+(b^p-b)-(c^p-c)+a+b-c.$$






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$endgroup$





















    3












    $begingroup$

    By Fermat's little theorem, $0equiv a^p+b^p-c^pequiv a+b-cpmod p$.






    share|cite|improve this answer











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      2 Answers
      2






      active

      oldest

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      2 Answers
      2






      active

      oldest

      votes









      active

      oldest

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      active

      oldest

      votes









      5












      $begingroup$

      Write $$a^p+b^p-c^p=(a^p-a)+(b^p-b)-(c^p-c)+a+b-c.$$






      share|cite|improve this answer









      $endgroup$


















        5












        $begingroup$

        Write $$a^p+b^p-c^p=(a^p-a)+(b^p-b)-(c^p-c)+a+b-c.$$






        share|cite|improve this answer









        $endgroup$
















          5












          5








          5





          $begingroup$

          Write $$a^p+b^p-c^p=(a^p-a)+(b^p-b)-(c^p-c)+a+b-c.$$






          share|cite|improve this answer









          $endgroup$



          Write $$a^p+b^p-c^p=(a^p-a)+(b^p-b)-(c^p-c)+a+b-c.$$







          share|cite|improve this answer












          share|cite|improve this answer



          share|cite|improve this answer










          answered Jan 29 at 6:41









          Michael RozenbergMichael Rozenberg

          109k1896201




          109k1896201























              3












              $begingroup$

              By Fermat's little theorem, $0equiv a^p+b^p-c^pequiv a+b-cpmod p$.






              share|cite|improve this answer











              $endgroup$


















                3












                $begingroup$

                By Fermat's little theorem, $0equiv a^p+b^p-c^pequiv a+b-cpmod p$.






                share|cite|improve this answer











                $endgroup$
















                  3












                  3








                  3





                  $begingroup$

                  By Fermat's little theorem, $0equiv a^p+b^p-c^pequiv a+b-cpmod p$.






                  share|cite|improve this answer











                  $endgroup$



                  By Fermat's little theorem, $0equiv a^p+b^p-c^pequiv a+b-cpmod p$.







                  share|cite|improve this answer














                  share|cite|improve this answer



                  share|cite|improve this answer








                  edited Jan 29 at 15:03









                  J. W. Tanner

                  4,0611320




                  4,0611320










                  answered Jan 29 at 6:48









                  Chris CusterChris Custer

                  14.2k3827




                  14.2k3827






























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