Answer
Choice G
Work Step by Step
The Center-Radius Form of the equation of circles is given by $
(x-h)^2+(y-k)^2=r^2
,$ where $(h,k)$ is the center and $r$ is the radius. Using the Center-Radius Form, the given equation, $
(x-5)^2+(y+1)^2=81
,$ is equivalent to
\begin{align*}\require{cancel}
&
(x-5)^2+(y-(-1))^2=9^2
.\end{align*}
Therefore, the center of the radius in the equation above is $(5,-1).$ Hence, Choice G.
