This is LaTeX code:
[latex]
\left[\begin{array}{c} x \\ y \\ z \end{array}\right] = \left[\begin{array}{c} 4 \\ 0 \\ -6 \end{array}\right] + t \left[\begin{array}{c} -7 \\ 1 \\ 9 \end{array}\right]
[/latex]