We take the equation : $(F): x^7 \equiv 2 (mod5)$
Let be $x$ the solution of $(F)$
Prove that: $$x \wedge 5=1$$
I'm lost please give me a help
We take the equation : $(F): x^7 \equiv 2 (mod5)$
0
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number-theory
elementary-number-theory
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2The notation $$x \wedge 5$$ means what? – 2017-02-24
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0i have found only $x=3$ – 2017-02-24
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0@quasi pgcd(x,5) – 2017-02-24
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0@quasi, or in English, just $\gcd (x, 5)$. It appears user281932 is a French speaker. – 2017-02-24
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0@user281932 - there are only 5 possible values of $x \mod 5$ so it is simple to test all of them. As Dr. Graubner has stated only $3$ solves the equivalence. $x$ itself can be any number of form $3 + 5n$, but all such numbers clearly have $gcd(x, 5) = 1$. – 2017-02-24