已知x²+y²=4,xy=-2,x
来源:学生作业帮助网 编辑:作业帮 时间:2024/09/08 12:43:10
![已知x²+y²=4,xy=-2,x](/uploads/image/z/5251131-27-1.jpg?t=%E5%B7%B2%E7%9F%A5x%26%23178%3B%2By%26%23178%3B%3D4%2Cxy%3D-2%2Cx)
x){}K+Ԕ
-+!NENMR>A5v6ęQ] mєkUTB$LtM 0@ݨ|.Jd#vhTVj/.H̳:Ar67@myԱa%jU( S3k
已知x²+y²=4,xy=-2,x
已知x²+y²=4,xy=-2,x
已知x²+y²=4,xy=-2,x
(x+y)²
=x²+y²+2xy
=4-4
=0
所以x+y=0
所以x²-y²
=(x+y)(x-y)
=0
(x+y)²=x²+y²+2xy=0
∴x+y=0
∴x²-y²=(x+y)(x-y)=0