若3^x=6,9^y=2,求3^2x-4y+2
问题描述：
若3^x=6,9^y=2,求3^2x-4y+2
答
3^2x=(3^x)^2=6^2=36
3^-4y=1/3^4y=1/9^2y=1/(9^y)^2=1/4
3^2x-4y+2
=36x1/4x9
=81