=(x+y-z)(x-y+z)/(x+y+z)((x+y-z)
=(x-y+z)/(x+y+z)那x∧2-(y-z)∧2/(x-y)∧2-z∧2该怎么算呢？=(x+y-z)(x-y+z)/(x-y+z)(x-y-z)=(x+y-z)/(x-y-z)