x/慎拿(x+1)-(x-1)/(x-2)=a/(x^2-x-2)
x(x-2)/(x+1)(x-2)-(x-1)(x+1)/(x+1)(x-2)=a/(x^2-x-2)
(x^2-2x-x^2+1)/(x+1)(x-2)=a/(x^2-x-2)
(1-2x)/(x^2-x-2)=a/(x^2-x-2)
1-2x=a
2x=1-a
x=(1-a)/2
因为宽昌搭x<0,所以(1-a)/迅搏2<0,1-a<0,a>1
同时去局旁分母,同时哗腊姿乘以(x^2-x-2)
x(x-2)-(x-1)(x+1)=a
x^2-2x-x^2+1=a
-2x+1=a
x=(1-a)/乱绝2<0
a>1