[tex]\bf \textit{equation of a circle}\\\\
(x-{{ h}})^2+(y-{{ k}})^2={{ r}}^2
\qquad
\begin{array}{lllll}
center\ (&{{ h}},&{{ k}})\qquad
radius=&{{ r}}
\end{array}\\\\
-----------------------------\\\\
x^2+y^2=49\iff (x-0)^2+(y-0)^2=7^2\quad
\begin{cases}
h=0\\
k=0
\end{cases}
\\\\\\
(x-\underline{(-3)})^2+(y-\underline{(+4)})^2=7^2\quad
\begin{cases}
h=-3\\
k=4
\end{cases}
\\\\\\
\boxed{(x+3)^2+(y-4)^2=49}[/tex]
