Right.

I would start by dividing thorugh by 2. Then complete the squares:

Given that the circle is tangent to the x axis, the distance from the center to the x-axis is equal to the radius of the circle. The y-coordinate of the center is 3, so that's the radius. Remember that the right jand side is the square of the radius, and 3^2 = 9.

I think this is in error. The distance from the center at (-1,3) to the line y=2 is 1, so the right hand side should be 1, not 2.