The centre and radius of the sphere, `x^2 + y^2 + z^2 + 4x - 8y - 2z = 5` is ..................
(-2, 4, -1) ; `sqrt(26)` uts
(1, 4, -1) ; `sqrt(36)` uts
(1, 1, -4) ; `sqrt(21)` uts
(1, 0, 0) ; `sqrt(13)` uts
explain