1. Considering the points A and B, you can conclude that the center lies in the straight line y = x, which is the angle bisector of the first and the third quadrants right angle. 2. Considering the points B and C, you can conclude that the center lies in vertical line x = -1. 3. From n1) and n2), it follows that the center is the point (x,y) = (-1,-1). 4. The radius is= = . 5. Thus the equation of the circle is = 10.