Okay, here we have this:
Considering the provided equation, we are going to graph it, so we obtain the following:
We can see that the equation fulfills the following form of the standard equation of a circle: (x-a)²+(y-b)²=r².
Where the center of the circle corresponds to (a, b) and the radius is r, therefore from the equation we obtain:
a=0
b=-4
r²=4 --> r=2
According to this we have that the center of the circle of the equation is (0, -4) and has a radius of 2. Therefore, when graphing we obtain the following: