2^2n＋1等于7,2^2＋m等于5,求2^3n-m等于?
问题描述：
2^2n＋1等于7,2^2＋m等于5,求2^3n-m等于?
答
2^2n?表示2的2n次方?
解得（6√6 ）-1
2^2n+1?表示2的2n+1次方?
2^2n＋1=7推出2^n*2^n*2=7即2^n=√(7/2)
2^2+m=5推出4*2^m=5即 2^m=5/4
所以2^3n-m=(2^n)^3/2^m
=[√(7/2)]^3/(5/4)
=(7/5)*√14