解:﹙x²-6x+9﹚+﹙y²+10y+25﹚=0 ﹙x-3﹚²+﹙y+5﹚岁神²=0 ∵ ﹙x-3﹚²≥型雀搭0, ﹙y+5﹚卜拿²≥0 又: ﹙x-3﹚²+﹙y+5﹚²=0 ∴ x-3=0, x=3 y+5=0, y=﹣5 x+y=3-5=﹣2.
(x -3)^2 + (y+5)^2 = 0 x =3 y = -5 x+y = -2