Question

Using the following equation, find the center and radius:
x2 - 4x + y2 + 8y = -4

a. The center is located at (-2, -4), and the radius is 4.
b. The center is located at (2, -4), and the radius is 4.
c. The center is located at (-2, -4), and the radius is 16.
d. The center is located at (2, -4), and the radius is 16.

Answer 1

You will need to write the equation in this form:

(x-h)^2 + (y-k)^2 = r^2 where (h,k) is the center and r is the radius.

Answer 2

(x-2)^2 + (y+4)^2 = 16 ?

Answer 3

(x-2)^2 + (y+4)^2 = 4^2 to highlight the radius.

Answer 4

Compare to this:

(x-h)^2 + (y-k)^2 = r^2 where (h,k) is the center and r is the radius.

Answer 5

.b. The center is located at (2, -4), and the radius is 4.