What is the equation of a circle with a center at (-3, -4) and a radius of 3?

It is: ${\left(x + 3\right)}^{2} + {\left(y + 4\right)}^{2} = 9$
The equatyion of a circle whose center is at $C = \left(a , b\right)$ and radius is $r$ is:
${\left(x - a\right)}^{2} + {\left(y - b\right)}^{2} = {r}^{2}$