x = (−b ± √(b² − 4ac))/(2a)

<var>x</var> = (&minus;<var>b</var> &PlusMinus; &radic;(<var>b</var><sup>2</sup> &minus; 4<var>a</var><var>c</var>))/(2<var>a</var>)

Or, just use GitHub’s new math support:

$x=\frac{-b\pm\sqrt{b^2-4ac}}{2a}$ and $$x=\frac{-b\pm\sqrt{b^2-4ac}}{2a}$$

$x=\frac{-b\pm\sqrt{b^2-4ac}}{2a}$ and $$x=\frac{-b\pm\sqrt{b^2-4ac}}{2a}$$

You can also write this in a single line style: $x=(-b\pm\sqrt{b^2-4ac})/(2a)$

$x=(-b\pm\sqrt{b^2-4ac})/(2a)$