智利甲规则:分解因式(x+y)^2+4(x-y)^2-4(x^2-y^2),脑子最近有点短路,有点昏头了哈,不要见笑
来源:百度文库 编辑:查人人中国名人网 时间:2024/10/06 10:42:39
呵呵
=x^2+2xy+y^2+4x^2-8xy+4y^2-4x^2+4y^2
=x^2-6xy+9y^2
=(x+3y)^2
(x+y-2(x-y))^2=(x+3y)^2
x^2-6xy+9y^2=(x-3y)^2
=x^2+2xy+y^2+4x^2-8xy+4y^2-4x^2+4y^2
=x^2-6xy+9y^2
=(x+3y)^2
(x+y-2(x-y))^2=(x+3y)^2
x^2-6xy+9y^2=(x-3y)^2