Answer:
x^{2} +2x+y^{2}+2y= 18
Step-by-step explanation:
equation of circle is:
[tex]x^{2}+y^{2}=r^{2}[/tex]
using distance formula and substituting value,
[tex](3-(-1))^{2} +(1-(-1))^{2}=r^{2}[/tex]
solving,
r=[tex]2\sqrt{5}[/tex]
for equation of circle,
[tex](x-(-1))^{2} +(y-(-1))^{2} =20[/tex]
on solving,
[tex]x^{2} +2x+1+y^{2}+2y+1=20[/tex]
on solving,
[tex]x^{2} +2x+y^{2}+2y= 18[/tex]
