已知xy≠0,且2x+3xy-2y=0,求(x+y)/(x-y)的值.
问题描述：
已知xy≠0,且2x+3xy-2y=0,求(x+y)/(x-y)的值.
答
2X^2+3xy-2y^2=0 (2x-y)(x+2y)=0 即：2x-y=0或,x+2y=0 y=2x或x=-2y 当y=2x时：x+y/x-y=3x/(-x)=-3 当x=-2y时：x+y/x-y=-y/(-3y)=1/3