a) By looking at their intersection and their direction vectors, show that the following lines are skew:

(x,y,z) = (2, -1, 6) + t(1, 2, 0)

and

(x, y, z) = (1, 4, 4) + u(2, -3, 1).

b) Find the closest point to the origin on the line (x,y,z) = (2, -1, 6) + t(1, 2, 0) and the shortest distance from the origin to that line.