I am writing the following syntax to get a conditional equation. But the equation is not numbered. How can I number it?

```
\[
f(x) = \begin{cases}
x+7 & \text{if $5< x$}; \\
x^2-3 & \text{if $-3 \le x \le 5$};\\
-x & \text{if $x < -3$}.
\end{cases}
\]
```

## Best Answer

Instead of using

`\[...\]`

, you can use the`align`

command. The MWE (minimum working example) is presented below:Update：