Question

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A=4^0 + 4^1 + 4^2 + 4^3 +.... 4^99 chia hết cho 31

Answer 1

[Nguyễn Lê Phước Thịnh]

\(A=\left(1+4+4^2+4^3+4^4\right)+...+4^{95}\left(1+4+4^2+4^3+4^4\right)\)

\(=341\cdot\left(1+...+4^{95}\right)⋮31\)