Let (h, k) be the center of the circle
And the distance from this point to each of the points will be equal (the radius)
So we have this equation
( h - - 7)^2 + (k - 0)^2 = ( h - 7)^2 + (k - 0 )^2
(h + 7)^2 = ( h - 7)^2
h^2 + 14h + 49 = h^2 - 14h + 49
14h = - 14 h
28h = 0
h = 0
And we can solve for k, thusly
(0 - 7)^2 + ( k -0)^2 = ( 0 - - 3)^2 + (k - 4)^2
49 + k^2 = 9 + k^2 - 8k + 16
49 = 25 - 8k
8k = 25 - 49
8k = - 24
k = -3
So......the center of the circle is ( 0, - 3)
And the radius is given by √ [ (0 - 7)^2 + ( -3 - 0)^2 ] = √ [ 49 + 9] = √58
So... the equation of the circle is
(x - h)^2 + ( y - k)^2 = r^2
( x - 0)^2 + ( y - - 3)^2 = 58
x^2 + ( y + 3)^2 = 58
Here is a pic : https://www.desmos.com/calculator/m2ugumny98