Simple math
When \(a \ne 0\), there are two solutions to \(ax^2 + bx + c = 0\) and they are
\[x_1 = {-b + \sqrt{b^2-4ac} \over 2a}\] \[x_2 = {-b - \sqrt{b^2-4ac} \over 2a} \notag\]You need set mathjax: true in the _config.yml or the markdown’s front matter to enable it.
After MathJax enabled, you can set mathjax_autoNumber: true to have equations be numbered automatically, You can use \notag or \nonumber to prevent individual equations from being numbered.
Matrices
\[\begin{pmatrix} 1 & a_1 & a_1^2 & \cdots & a_1^n \\ 1 & a_2 & a_2^2 & \cdots & a_2^n \\ \vdots & \vdots& \vdots & \ddots & \vdots \\ 1 & a_m & a_m^2 & \cdots & a_m^n \end{pmatrix}\]More
More syntax: MathJax basic tutorial and quick reference