Answer
$${\text{Neither orthogonal nor parallel}}$$
Work Step by Step
$$\eqalign{
& {\text{Let }}{\bf{u}} = \left\langle { - 4,3, - 6} \right\rangle ,{\text{ }}{\bf{v}} = \left\langle {16, - 12,24} \right\rangle \cr
& {\text{Find }}{\bf{u}} \cdot {\bf{v}} \cr
& {\bf{u}} \cdot {\bf{v}} = \left\langle { - 4,3, - 6} \right\rangle \cdot \left\langle {16, - 12,24} \right\rangle \cr
& {\bf{u}} \cdot {\bf{v}} = - 64 - 36 - 144 \cr
& {\bf{u}} \cdot {\bf{v}} = - 244 \ne 0 \cr
& {\text{Therefore, the vectors are not orthogonal}}{\text{.}} \cr
& {\text{Neither orthogonal nor parallel}} \cr} $$
