年级 | 科目 | 问题描述 | 提问时间 |
初二 | 数学 | 星号题 | 2014-07-07 12:12:21 |
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学点点闵老师 2014-07-07 12:36:10 | |||
xy(x2-y2)+yz(y2-x2+x2-z2)+zx(z2-x2) =(xy-yz)(x2-y2)+(yz—xz)(x2-z2) =(x-y)(x-z)(y(x+y)-z(x+z)) =(x-y)(x-z)(x+y+z)(y-z) | |||
学点点闵老师 2014-07-07 12:36:34 | |||
xy(x2-y2)+yz(y2-x2+x2-z2)+zx(z2-x2) =(xy-yz)(x2-y2)+(yz—xz)(x2-z2) =(x-y)(x-z)(y(x+y)-z(x+z)) =(x-y)(x-z)(x+y+z)(y-z) |