## Align

If there are several equations that align would be applicable.

\begin{align}
y &= 2x + 3x + 4z + 5z \\
&= 5x + 4z + 5z \\
&= 5x + 9z
\end{align}
$\begin{array}{rl}y& =2x+3x+4z+5z\\ & =5x+4z+5z\\ & =5x+9z\end{array}$

## Matrix

\left[
\begin{matrix}
x_{11} & x_{12} \\
x_{21} & x_{22}
\end{matrix}
\right]
$\left[\begin{array}{cc}{x}_{11}& {x}_{12}\\ {x}_{21}& {x}_{22}\end{array}\right]$
\left[
\begin{matrix}
x_{11} & \cdots & x_{1n} \\
\vdots & \ddots & \vdots \\
x_{m1} & \cdots & x_{mn}
\end{matrix}
\right]
$\left[\begin{array}{ccc}{x}_{11}& \cdots & {x}_{1n}\\ ⋮& \ddots & ⋮\\ {x}_{m1}& \cdots & {x}_{mn}\end{array}\right]$