当k=多少时,分式方程k/x+1+x/x-1-x/x+1=0有增根

Question

当k=多少时,分式方程k/x+1+ x/x-1- x/x+1=0有增根

Answer 1

分式两边同时乘以（x+1)(x-1)化简得
k(x-1)+2x=0
x=1时,2=0舍去
x=-1时,-2k-2=0
k=-1