约分:(x+y)² -z²分之x²-(y-z)²

问题描述:

约分:(x+y)² -z²分之x²-(y-z)²

Tiamo_碓冰,你好: [x²-(y-z)²]/[(x+y)²-z²].分母是(x+y)²-z²,分子是x²-(y-z)²=[(x+y-z)(x-y+z)]/[(x+y+z)(x+y-z)].用平方差公...