(x-8)/(x-7)-1/(7-x)=8
(x-8)/(x-7)+1/(x-7)=8
两边乘x-7
x-8+1=8(x-7)
x-7=8(x-7)
7(x-7)=0
x-7=0
所以分母x-7为0,是增根,舍去
所以方程无解