Test

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

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

$$\sum_{i=0}^n i^2 = \frac{(n^2+n)(2n+1)}{6}$$

A 3x3 matrix: $$((1,2,3),(4,5,6),(7,8,9))$$

$$x = (-6 +- sqrt((-6)^2 - 4 (1)(4)))\frac(2 xx 1)$$

$$\displaystyle \int$$