The equation of the circle that passes through (-1,6) and which has a center at (2,3) can be written as x^2 + y^2 + Ax + By + C = 0. Find A * B * C.
An equation for a circle is: (x - h)2 + (y - k)2 = r2 where the center is (h, k) and the radius is r.
Center = (2, 3) ---> h = 2 and k = 3
The distance from the center to the point (-1, 6) is a radius: r = sqrt( (-1 - 2)2 + (6 - 3)2 ) = sqrt(18)
Equation: (x - 2)2 + (y - 3)2 = 18
Now expand this equation to get it into the proper form ...