直接引入<head>和<body>标签即可，注意math区块需要替换成2个$
<head>
<link rel="stylesheet" type="text/css" href="./test.css" />
<script type="text/x-mathjax-config">
MathJax.Hub.Config({tex2jax: {inlineMath: [['$','$'], ['\\(','\\)']]}});
</script>
<script type="text/javascript"
src="http://cdn.mathjax.org/mathjax/latest/MathJax.js?config=TeX-AMS-MML_HTMLorMML">
</script>
</head>
<body>
<p>
When $a \ne 0$, there are two solutions to \(ax^2 + bx + c = 0\) and they are:
<br> $$x = {-b \pm \sqrt{b^2-4ac} \over 2a}.$$
</p>
</body>
