用换元法解方程(x-1)/(x+2)-3/(x-1)-1=0
问题描述：
用换元法解方程(x-1)/(x+2)-3/(x-1)-1=0
答
(x-1)/(x+2)-3/(x-1)-1=0(x-1)/(x+2)-[(x+2)-(x-1)]/(x-1)-1=0(x-1)/(x+2)-(x+2)/(x-1)+1-1=0(x-1)/(x+2)-(x+2)/(x-1)=0设(x-1)/(x+2)=y,则y-1/y=0即：y²-1=0,解得：y1=1 y2=-1即：(x-1)/(x+2)=1,或者(x-1)/(x+...