Question

[Võ Ngọc Phương Uyên]

CMR

1)\(81^7-27^9-9^{13}\)chia hết cho 45

2)\(3^{n+2}-2^{n+2}+3^n-2^n\)chia hết cho 10

3)\(3^{n+3}+3^{n+1}+2^{n+2}+2^{n+3}\)chia hết cho 6