If you have two vectors in space (so 3d) and they don't intersect, am I right in saying that it doesn't make sense to say they form a plane? Because there's no single plain we could be talking about. Whereas if they do intersect, they will always form a plane where those two lines are part of right? And is it right to say if you have 3 vectors in space, a, b, and c, and three constants p, q and r, if you can write pa + qb = rc then they all lie on a plane? Thanks.