x/(x+3)-x/(3-x)=18/(x平方-9)

问题描述:

x/(x+3)-x/(3-x)=18/(x平方-9)

x/(x+3)-x/(3-x)=18/(x平方-9﹚
x/﹙x+3﹚+x/﹙x-3﹚=18/﹙x+3﹚﹙x-3﹚
x﹙x-3﹚+x﹙x+3﹚=18
2x²=18
x=±3