<!DOCTYPE html>
<html>
<head>
<title>数学方程式</title>
<style type="text/css">
body { background-color: #F2FFC1; }
h2 { color: red; text-align: center; }
hr { width: 80%; height: 2px; background-color: blue; border: none; }
p { font-size: 36px; text-align: center; }
</style>
</head>
<body>
<h2>数学方程式</h2>
<hr>
<p>2x<sup>2</sup> + 3x = 9</p>
<p>x<sub>1</sub> + x<sub>2</sub> = 10</p>
</body>
</html>