This is an inline math expression: $\frac{-b\pm\sqrt{{{b}^{2}}-4ac}}{2a}$.
This is displayed:
\[\begin{matrix} 1 & 2 & \phi & \pi \\ \theta & \beta & \sqrt{2} & \partial x \\ a\otimes b & \lambda & \Gamma & {{\pi }^{2}} \\ 4! & \Xi & \Delta y & -3 \\ \end{matrix}\]