引用
最初由 ほしな歌唄 发布
x^2+xy+4x-2y^2+5y+3
=(x+2)^2+y(x+2)-2y^2+3y-1
=(x+2)^2+y(x+2)-(2y-1)(y-1)
=(x+2+2y-1)(x+2-y+1)
=(x+2y+1)(x-y+3)
不是很简单么,搞那么复杂干啥。
抱歉,我糊涂了。
x^2+xy+4x-2y^2+5y+3
Rearrange
=(x^2+4x=4)+(xy+5y)-2y^2-1
Simplify
=(x+2)^2+(x+2)y+3y-2y^2-1
Rearrange
=(x+2)^2+(x+2)y+(-2y^2+3y-1)
Simplify
=(x+2)^2+(x+2)y+(-2y-1)(y-1)
=(x+2)^2+y(x+2)-(2y-1)(y-1)
然后,这是怎么一回事?
可以把省略的步骤列出吗?
=(x+2+2y-1)(x+2-y+1)
=(x+2y+1)(x-y+3)