let be A(-5,-4) and B(7,12)

middle of AB is center O((-5+7)/2 , (-4+12)/2) = O(1, 4)

distance AB is diameter d = √((-5-7)^2+ (-4-12)^2) = √400 = 20

the radius is d/r = 20/2 = 10

the equation of circle is

(x−h)^2+(y−k)^2=r^2

h and k are the coordinates of the center of the circle, r is the radius

(x - 1)^2 + (y - 4)^2 = 10^2

(x - 1)^2 + (y - 4)^2 = 100