Question

7⁶+7⁵+7⁴+7³+7²+7 chia hết cho 56 hay không? Vì Sao?

Answer 1

\(7^6+7^5+7^4+7^3+7^2+7=\left(7^6+7^5\right)+\left(7^4+7^3\right)+\left(7^2+7\right)\)

\(=56.7^4+56.7^2+56.1=56.\left(7^4+7^2+1\right)\)

Chia hết cho 56