Find the equation of set of points which moves so that its distances from points A (3, 4, - 5) and B (-2, 1, 4) are equal.

Find the octant in which the following points lie:
A (-3,1, 2), B (-3, 1, -2), C (-3, -1,-2), D (3, -1, -2) and E (3,1, 2).

Find the perpendicular distance of point A (-3, 2, -4) from:
(a) ZX-plane      (b)XY-plane         (c) YZ-plane.