MathJax is installed
Mathjax: $$x = {-b \pm \sqrt{b^2-4ac} \over 2a}.$$
Produces: $$x = {-b \pm \sqrt{b^2-4ac} \over 2a}.$$
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Mathjax: $$x = {-b \pm \sqrt{b^2-4ac} \over 2a}.$$
Produces: $$x = {-b \pm \sqrt{b^2-4ac} \over 2a}.$$