a circle has a radius of 12 and a center at(-7,4) . find the equation of the circle. a. x^2 y^2=3.46 b. (x 7)^2 (y-4)^2=144 c. (x-7)^2 (y-4)^2=144 d. (x-4)^2 (y 7)^2=144