Answer
$(x-2)^{2}+(y+3)^{2}=45$
Work Step by Step
A circle has the form:
$(x-h)^2+(y-k)^2=r^2$ with center $(h,k)$ and radius $r$
We know that the center is $(2,-3)$ and the radius is $3\sqrt{5}$. Thus:
$(x-h)^2+(y-k)^2=r^2$
$(x-2)^{2}+[y-(-3)]{2}=(3\sqrt{5})^{2}$
$(x-2)^{2}+(y+3)^{2}=45$