81的2x方÷9的2x方÷3的x方=81,则x= ;若3的m方=6,3的n方=2,则3的(2m-3n)方=

问题描述:

81的2x方÷9的2x方÷3的x方=81,则x= ;
若3的m方=6,3的n方=2,则3的(2m-3n)方=

81^2X÷9^2X÷3^X=81
3^8X÷3^4X÷3^X=3^4
8X-4X-X=4
X=12
3^M=6 3^N=2
3^(2M-3N)=3^2M÷3^3N=(3^M)^2÷(3^N)^3
=6^2÷2^3=36÷8=4.5

1.81的2x方等于3的8x方.同理可得分式化解为3的3x方等于81.所以x为4/3 2.3的(2m-3n)方等于3的2m方除以3的3n方 所以等于36/8=4.5