4^m*8^m-1*2^m的值是512,那么m的值是?

题目

4^m*8^m-1*2^m的值是512,那么m的值是?

答案

4^m×8^(m-1)×2^m
=2^(2m)×2^[3(m-1)]×2^m
=2^[2m+3(m-1)+m]
=2^(6m-3)
=512
=2^9
6m-3=9
m=2