[tex](\stackrel{x_1}{2}~,~\stackrel{y_1}{-15})\qquad (\stackrel{x_2}{14}~,~\stackrel{y_2}{r}) \\\\\\ \stackrel{slope}{m}\implies \cfrac{\stackrel{rise} {\stackrel{y_2}{r}-\stackrel{y1}{(-15)}}}{\underset{run} {\underset{x_2}{14}-\underset{x_1}{2}}}~~ = ~~\stackrel{\stackrel{m}{\downarrow }}{\cfrac{3}{4}}\implies \cfrac{r+15}{12}~~ = ~~\cfrac{3}{4}\implies r+15 = \cfrac{12\cdot 3}{4} \\\\\\ r+15=9\implies \boxed{r=-6}[/tex]
