This is LaTeX code:

[latex]
\left[
\begin{array}{c}
3 \\
0
\end{array}
 \right]
+ t
\left[
\begin{array}{c}
2\\
1
\end{array}
\right]
=
\left[
\begin{array}{c}
x\\
y
\end{array}
\right]
[/latex]