controle

$
\begin{array}{l}
\left( {\begin{array}{*{20}c}
4\\
0\\
{-3}\\
\end{array}} \right) \cdot \left( {\begin{array}{*{20}c}
3\\
2\\
4\\
\end{array}} \right) = 12 - 12 = 0 \\
\left( {\begin{array}{*{20}c}
0\\
2\\
{-1}\\
\end{array}} \right) \cdot \left( {\begin{array}{*{20}c}
3\\
2\\
4\\
\end{array}} \right) = 4 - 4 = 0 \\
\end{array}
$

klopt