Answer:
We draw the circles on a coordinate system. We know that a circle is has points that are equidistant from its centerpoint. So the point where these circles are tangent is the midpoint between the centerpoints.
We can use the midpoint formula.
M = ((x1 + x2) / 2 , (y1 + y2) / 2)
M = ((-2 + 6) / 2 , (3 + 9) / 2)
M = (2, 6)
These circles will have the same radii.
If we take the distance between the midpoint and (-2,3), we will have the radius of the circle with this centerpoint.
If we take the distance between the midpoint and (6,9), we will have the radius of the circle with this centerpoint.
Explanation: