通分
(2x-8)/(x^2-8x+12)=(2x-8)/(x^2-8x+7)
(2x-8)/(x^2-8x+12)-(2x-8)/(x^2-8x+7)=0
(2x-8)[1/(x^2-8x+12)-1/(x^2-8x+7)]=0
x^2-8x+12≠x^2-8x+7
所以1/(x^2-8x+12)-1/(x^2-8x+7)≠0
所以2x-8=0
x=4
分式方程要检验
经检验,x=4是方程的解