Altitudes of tetrahedron intersect, coordinate vectors

A tetrahedron has vertices A, B, C and D with coordinate vectors for the points being:

$\displaystyle \mathbf{a}=\begin{pmatrix}0\\1\\2\end{pmatrix},\ \mathbf{b}=\begin{pmatrix}-1\\4\\1\end{pmatrix},$ $\displaystyle \mathbf{c}= \begin{pmatrix}1\\0\\3\end{pmatrix},\ and\ \mathbf{d}=\begin{pmatrix}-3\\1\\2\end{pmatrix}$

Find parametric vector equations for the two altitudes of the tetrahedron which pass through the vertices A and B, and determine whether the two altitudes intersect or not.

Altitude is a line through the vertex and perpendicular to the opposite face.

For my altitudes, I managed to get:

$\displaystyle \mathbf{x}=\begin{pmatrix}0\\1\\2\end{pmatrix}+\la mbda\begin{pmatrix}-2\\6\\14\end{pmatrix} and\ \mathbf{x}=\begin{pmatrix}-1\\4\\1\end{pmatrix}+\lambda\begin{pmatrix}0\\-3\\3\end{pmatrix}$

Not too sure if that's right