Is there a way to remove the right vertical line in the following matrix?

[![Enter image description here](https://i.stack.imgur.com/I5rdi.png)](https://i.stack.imgur.com/I5rdi.png)

```
\documentclass{article}
 \usepackage{amsmath}
\begin{document}
   $    \begin{vmatrix} \alpha & -& \beta =180\\ \alpha & +&\beta =68
\end{vmatrix}$  
\end{document}

```