Question

计算（x-y+z）的二次方减（x+y-z）的二次方

方法请给简便。。求过程。。。

Answer 1

x-y+z=x-(y-z)
设y-z=m
则，原式可变为（x-m)的二次方减去(x+m)的二次方
展开分解计算后，得4xm
再把m代入，可得出答案

Answer 2

=[(x-y+z)+(x+y-z)][(x-y+z)-(x+y-z)]
=2x(-2y+2z)
=-4xy+4xz

Answer 3

(x-y+z)^2-(x+y-z)^2
=(x-y+z+x+y-z)(x-y+z-x-y+z)
=2x(2z-2y)
=4x(z-y)

Answer 4

平方差公式得：2x(2z-2y)=4x(z-y)

Answer 5

(x-y+z)^2-(x+y-z)^2=(x-y+z+x+y-z)(x-y+z-x-y+z)=2x(2z-2y)=4x(z-y)