Answer
$\color{blue}{(x+2)^2+(y-3)^2=225}$
Work Step by Step
RECALL:
The center-radius form of a circle whose center is at $(h, k)$ and whose radius is $r$ units is:
$(x-h)^2+(y-k)^2=r^2$
The given circle has its center at $(-2, 3)$ and has a radius of 15 units.
Thus, its equation in center-radius form is :
$(x-(-2))^2+(y-3)^2=15^2
\\\color{blue}{(x+2)^2+(y-3)^2=225}$
