Find an equation of the sphere that passes through the point (7, 4, -6) and has center (4, 7, 6).
Recall that the equation of a sphere with radius r and center (a, b, c) is given by
(x - a)^2 + (y - b)^2 + (z - c)^2 = r^2.
If the sphere passes through (7, 4, -6) and has center (4, 7, 6), then its radius is the distance between these two points.
Therefore,
r = sqrt((4 - 7)^2 + (7 - 4)^2 + (6 - (-6))^2)
= sqrt(9 + 9 + 144)
= sqrt(162).
Substituting this radius and the given center into the equation of a sphere, we therefore conclude that the equation of the given sphere is as follows.