Answer
$(x+3)^2+(y+3)^2=61$
Work Step by Step
The middlepoint between $(3,2)$ and $(-9,-8)$ is the center of the circle:
$\frac{(3,2)+(-9,-8)}{2}=(-3,-3)$, that is: $h=-3$, $k=-3$
The distance from the center to an endpoint is the radius:
$r=\sqrt {(-3-3)^2+(-3-2)^2}=\sqrt {36+25}=\sqrt {61}$
Equation of a circle:
$(x−h)^2+(y−k)^2=r^2$ (standard form)
$[x-(-3)]^2+[y-(-3)]^2=(\sqrt {61})^2$
$(x+3)^2+(y+3)^2=61$
