Question 1199444
The x coordinate of the center must lie on the midpoint of the segment from
(-2,0) to (4,0). This is because the perpendicular bisector of any chord
of a circle goes through the center.  Similarly, the y coordinate of the center
lies on the midpoint between (0,2) and (0,-4). Thus the center of the circle is
(1,-1). The radius is the distance from the center to any point.
Thus r = sqrt((0-1)^2 + (2--1)^2) = sqrt(10)
So the equation is (x-1)^2 + (y+1)^2 = 10