3x=8y
x/y=8/3
（1）x+y/y
=x/y+1
=8/3+1
=11/3
(2)2x+3y/x-2y
分子分母同时除以y得
=(2x/y+3)/(x/y-2)
=(16/3+3)/(8/3-2)
=(25/3)/(2/3)
=25/2