x²+y²+4x+3y+13=0,算4x+6y

x²+y²+4x+6y+13=0
(x+2)²+(y+3)²=0
由非负性
x+2=0
y+3=0
解得
x=-2
y=-3
则
4x+6y
=-8-18
=-26

题目对吗?那个+3y应该是+6y吧
x²+y²+4x+6y+13=0
(x²+4x+4)+(y²+6y+9)=0
(x+2)²+(y+3)²=0
x=-2,y=-3
4x+6y
=4*(-2)+6*(-3)
=-8-18
=-26

灰常简单的啦,关键是凑完全平方
(x+2)²+(y+3)²=0
得x=-2,y=-3
4x+6y
=-8-18
=-26