Mathematics

Problem

Show that the vectors

\boldsymbol{i} - \boldsymbol{j} - \boldsymbol{k}, 2 \boldsymbol{i} + 3 \boldsymbol{j} + \boldsymbol{k}

and

7 \boldsymbol{i} + 3 \boldsymbol{j} - 4 \boldsymbol{k}

are coplanar.