Question

分解因式（x+y+z)²-(x-y-z)²

Answer 1

平方差
原式=(x+y+z+x-y-z)(x+y+z-x+y+z)
=2x(2y+2z)
=4x(y+z)

Answer 2

＝﹙x+y+z+x-y-z) ×(x+y+z-x+y+z) ........先用平方差

＝2x ×2(y+z)

＝4xy+4xz

Answer 3

（x+y+z）²-（x-y-z)²=（x+y+z+x-y-z)(x+y+z-x+y+z）=4x（y+z)..。

Answer 4

平方差公式，就是a²-b²=（a+b）（a-b），记住就好了