Matrix and Math ... with Latex

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

Type	LaTeX markup	Renders as
Plain	\begin{matrix} 1 & 2 & 3\\ a & b &c \end{matrix}	$$\begin{array}{ccc}1& 2& 3\\ a& b& c\end{array}$$
Parentheses round brackets	\begin{pmatrix} 1 & 2 & 3\\ a & b & c \end{pmatrix}	$$\left(\begin{array}{ccc}1& 2& 3\\ a& b& c\end{array}\right)$$
Brackets square brackets	\begin{bmatrix} 1 & 2 & 3\\ a & b & c \end{bmatrix}	$$\left[\begin{array}{ccc}1& 2& 3\\ a& b& c\end{array}\right]$$
Braces curly brackets	\begin{Bmatrix} 1 & 2 & 3\\ a & b & c \end{Bmatrix}	$$\left\{\begin{array}{ccc}1& 2& 3\\ a& b& c\end{array}\right\}$$
Pipes	\begin{vmatrix} 1 & 2 & 3\\ a & b & c \end{vmatrix}	$$\left|\begin{array}{ccc}1& 2& 3\\ a& b& c\end{array}\right|$$
Double pipes	\begin{Vmatrix} 1 & 2 & 3\\ a & b & c \end{Vmatrix}	$$\Vert \begin{array}{ccc}1& 2& 3\\ a& b& c\end{array}\Vert$$