(a) Let P be a point in space that is not contained in the plane that passes through th...

(a) Let P be a point in space that is not contained in the plane that passes through the three noncollinear points A, B, and C. Show that the distance between P and is given by the expression

(b) Use the result of part (a) to find the distance between (1, 0,−1) and the plane containing the points (1, 2, 3), (2,−3, 1), and (2,−1, 0).