(a) An aircraft is flying in a straight line which passes through the points (-1,0,5.6) and (2.5,4.5,5.1) measured in kilometres. Find the equation of the line of the aircraft's path. Show that it is parallel to the ground which is described by the plane -3x + 3y + 6z = 3.
(b) A recent survey has found the position of three points, (-2,5,3), (-1,3,7) and (1,9,2) on a block of land. Find the equation of the plane through these three points.