[3] 3. (a) Show that ; given by r = 3+s = 3+s z = 1+42s is not parallel to the line ;: x(t) = [1,4, 1] + [3, 2, 1] but they do not intersect. [3] (b) Find a non-zero vector n that is orthogonal to both lines #; and ,. Show that ; and 5 lie in 2 parallel planes. Find general equations of the two parallel planes containing these lines. [Hint: If a line in R? with direction vector d lies in a plane with normal vector n, then d and n must be orthogonal.]