石砚警察抓女学生小说:初一数学

来源:百度文库 编辑:高考问答 时间:2024/04/29 14:45:42
1+x^2-y^2-z^2-2x+2yz

1+x^2-y^2-z^2-2x+2yz
=1-2x+x^2-y^2+2yz-z^2
=(1-x)^2-(y-z)^2
=(1-x+y-z)*(1-x-y+z)

1+x^2-y^2-z^2-2x+2yz
=(x-1)^2-(y+z)^2
=(x-1+y+z)(x-1-y-z)