(3) (a) Find the distance between the planes P1 : 9: + 2y 2z = 7 and P2 : x + 23; 2z = 5. (b) Is the point Q1 = (7,1,1) on the plane P1? Justify your answer. (c) Find the equation of the line L that contains Q1 and its direction vector is the normal vector of P1. (d) Find the intersection point Q2 of L and P2. (e) Use Q1 and Q2 to nd the equation of a plane P3 that is parallel and equidistant (same distance) to P1 and P2