The standard form of an equation of a circle is,
Where
(h, k) is the center
r is the radius
The first equation is that of a circle.
Now,
The second equation is,
This is an equation of a parabola (quadratic).
When a circle and parabola intersect (solution point), there can be maximum 4 solutions, or 4 intersecting points.
The graphs of the two equations are shown: