2x/(x+2)-1/(x-2)=2
通分 [2x (x-2)-(x+2) ] / (x-2)(x+2) =2
化简（2x方-5x-2 ）/ (x-2)(x+2) =2
2x方-5x-2=2 (x-2)(x+2)
2x方-5x-2 = 2x方-8
x= 6/5