(a²-b²-c²)²-4b²c²=(a²-b²-c²＋2bc)(a²-b²-c²－2bc)=[a²－(b－c)²][a²－(b＋c)²]=(a＋b－c)(a－b＋c)*(a＋b＋c)(a－b－c)...确定对吗？是(a＋b－c)(a－b＋c)(a＋b＋c)(a－b－c) 吗中间的*应去掉,是我打快了.绝对正确!!谢啦