Answer
$(x+1)^2+(y+3)^2=9$
Work Step by Step
RECALL:
The standard form of a circle whose center is at $(h, k)$ and radius $r$ is $(x--h)^2+(y-k)^2=r^2$.
The center is at $(-1, -3)$, then $h=-1$ and $k=-3$.
The radius is 3 so $r=3$.
Thus, the standard form of the given circle's equation of the circle is:
$[x-(-1)]^2+[y-(-3)]^2=3^2
\\(x+1)^2+(y+3)^2=9$
