(x^m+2n)/(x^n=2)
=x^(m+2n-n)
=x^(m+n) = 16/2 =8
a^x+y=25
(a^x)(a^y)=25
5(a^y)=25
(a^y)=5
所以:a^x+a^y =5+5 =10