原式=[(x-y+z)(x+y-z)]/[(x+y-z)(x+y+z)] 注：根据a²-b²=（a-b）（a+b）
=（x-y+z)/(x+y+z)具体步骤。。请清楚点。。我觉得已经很具体了啊………………x²-(y-z)²/(x+y)²-z² =[x-(y-z)][x+(y-z)]/[(x+y)-z][(x+y)+z]拆开…………=[(x-y+z)(x+y-z)]/[(x+y-z)(x+y+z)] 消去(x+y-z)这项……=（x-y+z)/(x+y+z) 够具体了吧TAT