已知2^m=a,化简16×2^2m-1 ×2^3m-1 -4^m ×8^m
问题描述：
已知2^m=a,化简16×2^2m-1 ×2^3m-1 -4^m ×8^m
答
16×2^2m-1 ×2^3m-1 -4^m ×8^m =16×2^(2m-1) ×2^(3m-1) -4^m ×8^m =16×2^(2m-1+3m-1) -(2^2)^m ×(2^3)^m =4*2^2×2^(5m-2) -2^2m ×2^3m =4*2^(2+5m-2) -2^(2m+3m )=4*2^5m -2^5m=3*2^5m