若5^m=2 25^n=3,求5^2m-4n+3的值~
问题描述：
若5^m=2 25^n=3,求5^2m-4n+3的值~
答
5^m=2, 5^(2m)=2^2=4
25^n=3 得：5^(2n)=3, 所以：5^(4n)=9
5^2m-4n+3=5^2mx5^3/5^(4n)=4x125/9=500/9
答
5^2m-4n+3
=(5^m)^2÷(5^2)^2n×5^3
=(5^m)^2÷(25^n)^2×5^3
=2^2÷3^2×125
=500/9