（8X-800)/(5X-980)=8/3
==>(X-100)/(X-196)=8/3
==>3(X-100)=8(X-196)
==>3X-300=8X-1568
==>5X=1268
==>X=253.6
经检验X=253.6是原方程的根
故原方程的根是X=253.6.