What is the unit vector that is normal to the plane containing #(- 3 i + j -k)# and #(2i - 3 j +k )#?
you'll do this by calculating the vector cross product of these 2 vectors to get the normal vector
the unit normal is
you could check this by doing a scalar dot product between the normal and each of the original vectors, should get zero as they are orthogonal.
so for example