Question

(x+y-z)(x-y+z）-（x+y+z）（x-y-z）等于多少我要过程

用什么方法解

Answer 1

=(x+y-z)[x-(y-z)]-(x+y+z)[x-(y+z)]
=xf-(y-z)f-xf+(y+z)f
=(y+z)f-(y-z)f
=4yz
f为平方

Answer 2

平方差公式
原式=（x+（y-z））(x-(y-z))-(x+(y+z))(x-(y+z))
=x平方-（y-z）平方-x平方+（y+z）平方
=4yz

Answer 3

（x+y-z)(x-y+z）-（x+y+z）（x-y-z）
=（x+y-z）[x-（y-z）]-（x+y+z）[x-（y+z）]
=【x²-（y-z）²】-【x²-（y+z）²】
=（y+z）²-（y-z）²
=4yz