This circle passes through the points (-1, 2), (3,0) and (8,0). The center of the circle is at (h,k). What is the value of h+k?

\((x-h)^2+(y-k)^2=r^2 \)

Sub in your three points to get three equations and then solve them simultaneously.

Have you tried that?

If you are stuck then show us what you have done so far.

Note: I have not worked through this question but this is how I would start.