已知5^x=18,5^y=3,求25^(x-y)
问题描述：
已知5^x=18,5^y=3,求25^(x-y)
答
5^x=18,5^y=3
25^(x-y)=5^(2(x-y))=5^2x/5^2y=18^2/3^2=36