Find the unit vector please!?

Question

that is orthogonal to the plane through the points P = (3, -3, 0), Q = (5, -1, 2), and R = (5, -1, 6).

Answer 1

First find the two vectors PQ and PR. Now find the cross product of PQ and PR. That cross product is orthogonal to the plan containing the three points. Simply normalize it and you have your answer.