Answer
0
Work Step by Step
$\textbf{u}\times\textbf{v}=\begin{vmatrix}\hat{i}&\hat{j}&\hat{k}\\6&-2&8\\-9&3&-12\end{vmatrix}$$=\begin{vmatrix}-2&8\\3&-12\end{vmatrix}\hat{i}-\begin{vmatrix}6&8\\-9&-12\end{vmatrix}\hat{j}+\begin{vmatrix}6&-2\\-9&3\end{vmatrix}\hat{k}$
$=(24-24)\hat{i}-(-72-(-72))\hat{j}+(18-18)\hat{k}=0$
