已知5^m=a,125^n=b,求5^4m-6n

问题描述:

已知5^m=a,125^n=b,求5^4m-6n

125^n=b, 所以可得:5^(3n)=b
5^(4m-6n)
=5^(4m)/5^(6n)
=(5^m)^4/(5^3n)^2
=a^4/b^2