Respuesta :

Use (x - h)^2 + (x - k)^2 = r^2.

Note: (h, k) is the center of the circle.

(h, k) = (5, -4). This means h = 5 and k = -4.

Let r = radius

We now plug and chug.

(x - 5)^2 + (y -(-4))^2 = (8)^2

(x - 5)^2 + (y + 4)^2 = 64

Done.