Question

How do you find the center and radius of the the circle `(x-1)^2 + (y+1)^2 = 16`?

Answer 1

Centre is (1, -1) and radius is 4

Explanation:

You must first recall that the general circle equation is
`(x-h)^2 + (y-k)^2 = r^2` with centre (h, k)
Therefore all that needs to be done is reverse the sign of the other number in the bracket (in this case -1 and 1) and take the square root of 16 (which is 4)