Given the following equation:
We know that the equation of the circle with radius r and center (h,k) is:
in this case, we can associate the terms with x and y separately to get the following:
next, we can complete the square on both summands to get the following:
notice that we must add the terms to complete the square on both sides of the equation! IF we factorize the polynomials we get:
therefore, the x-coordinate of the center is h=-4
the y-coordinate of the ceter is k = 6
the radius is r = sqrt(76)