9^(m+3)×27^(m+1)÷3^(4m+7)=81
3^(2m+6)×3^(3m+3)÷3^(4m+7)=81
3^(2m+6+3m+3-4m-7)=3^4
2m+6+3m+3-4m-7=4
m+2=4
m=2