Matrix and Math ... with Latex

With MathJax we can use Latex language to introduce math expressions, equations in our webpages.
Sample:
$$x = {-b \pm \sqrt{b^2-4ac} \over 2a}.$$

Type	LaTeX markup	Renders as
Plain	\begin{matrix} 1 & 2 & 3\\ a & b &c \end{matrix}	\begin{matrix}1 & 2 & 3\\a & b & c\end{matrix}
Parentheses round brackets	\begin{pmatrix} 1 & 2 & 3\\ a & b & c \end{pmatrix}	\begin{pmatrix} 1 & 2 & 3\\ a & b & c \end{pmatrix}
Brackets square brackets	\begin{bmatrix} 1 & 2 & 3\\ a & b & c \end{bmatrix}	\begin{bmatrix}1 & 2 & 3\\a & b & c\end{bmatrix}
Braces curly brackets	\begin{Bmatrix} 1 & 2 & 3\\ a & b & c \end{Bmatrix}	\begin{Bmatrix}1 & 2 & 3\\a & b & c\end{Bmatrix}
Pipes	\begin{vmatrix} 1 & 2 & 3\\ a & b & c \end{vmatrix}	\begin{vmatrix}1 & 2 & 3\\a & b & c\end{vmatrix}
Double pipes	\begin{Vmatrix} 1 & 2 & 3\\ a & b & c \end{Vmatrix}	\begin{Vmatrix}1 & 2 & 3\\a & b & c\end{Vmatrix}