[tex]\bf (\stackrel{x_1}{-2}~,~\stackrel{y_1}{3})\qquad (\stackrel{x_2}{-2}~,~\stackrel{y_2}{-3}) ~\hfill \stackrel{slope}{m}\implies \cfrac{\stackrel{rise} {\stackrel{y_2}{-3}-\stackrel{y1}{3}}}{\underset{run} {\underset{x_2}{-2}-\underset{x_1}{(-2)}}}\implies \stackrel{~\hfill und efined}{\cfrac{-6}{-2+2}\implies \cfrac{-6}{0}}[/tex]
Check the picture below.
