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a fost răspuns

aratati xa numarul A=63^n+7^n+1*3^2n+1-21^n*3^n+2 este divizibil cu 13

Răspuns :

Falcuta205
[tex]A=63^{n}+7^{n+1}*3^{2n+1}-21^{n}*3^{n+2}\\ A=(7*3*3)^{n}+7^{n}*7*3^{2n}*3-(7*3)^{n}*3^{n}*3^{2}\\ A=7^{n}*3^{n}*3^{n}+7^{n}*3^{2n}*21-7^{n}*3^{n}*3^{n}*3^{2}\\ A=7^{n}*3^{2n}+7^{n}*3^{2n}*21-7^{n}*3^{2n}*9\\ A=7^{n}*3^{2n}*(1+21-9)\\A=7^{n}*3^{2n}*13\\Divizibil\ cu\ 13[/tex]

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