Step-by-step explanation:
Equation of circle with (h,k) as center and radius r is given by,
(x-h)²+(y-k)² = r²
Here we need to find the radius and center of the circle given by the equation (x+12)²+(y−4)²=81
Changing equation to (x-h)²+(y-k)² = r² form
(x+12)²+(y−4)²=81
(x-(-12))²+(y-4)² = 9²
So, h = -12 , k = 4 and r = 9
Center is (-12,4) and radius is 9
