若(y+2)²+x²-6x=-9,则x+y的值是1
若(y+2)²+x²-6x=-9,
则(y+2)²+(x²-6x+9)=0
(y+2)²+(x-3)²=0
y+2=0 y=-2
x-3=0 x=3
x+y=3-2=1