[tex]x^2+y^2-6x-10y+30=0\\
x^2-6x+9+y^2-10y+25-4=0\\
(x-3)^2+(y-5)^2=4\\
i) \left \{ {{x-3=0} \atop {y-5=2}} \right. \Leftrightarrow \left \{ {{x=3} \atop {y=7}} \right.\\
ii) \left \{ {{x-3=2} \atop {y-5=0}} \right. \Leftrightarrow \left \{ {{x=5} \atop {y=5}} \right. \\
S:(x,y)\in \{(3,7);(5,5)\}[/tex]
