x2+4x+y2-6y+13=0 xy等于几?

分类: 作业答案 • 2021-12-31 13:44:29

问题描述：

x2+4x+y2-6y+13=0 xy等于几?
x2+=x的二次方
x2+4x+y2-6y+13=0 则（2y)(x-2y)=?

答

x2+4x+y2-6y+13=0
(x+2)^2+(y-3)^2=0
x+2=0 y-3=0
x=-2 y=3
xy=-2*3=-6
(2y)(x-2y)
=-2*2*(-2-6)
=-2*2*(-8)
=32