The equation formula of the circle is (x-h)^2 + (y-k)^2 = r^2 where (h,k) the point of the center of the circle and (r) is the radius of the circle so if the center of the circle = (-2,-4) by subs. in the formula we get (x-(-2))^2 + (y-(-4))^2 = r^2 then the equation will be (x+2)^2 + (y+4)^2 = r^2 now we want to define the radius of the circle r since point (3,8) lay on the circle so we can then subs. in the equation to get the radius (x+2)^2 +(y+4)^2 = r^2 (3+2)^2 +(8+4)^2 = r^2 25 + 144 = r^2 r^2 = 169 r= 13 the radius of the circle is 13 so by subs in the equation we get (x+2)^2 + (y+4)^2 = 169 so it is the first answer in the choices
