X^2-(y-z)^2(x+y)^2-z^2

题目

X^2-(y-z)^2(x+y)^2-z^2
回答清楚一点啊!
约分的

答案

用平方差公式
x²-(y-z)²/(x+y)²-z²
=(x+y-z)(x-y+z)/(x+y+z)(x+y-z)
=(x-y+z)/(x+y+z)