[tex]\bf (\stackrel{x_1}{x}~,~\stackrel{y_1}{-7})\qquad (\stackrel{x_2}{-6}~,~\stackrel{y_2}{8}) \\\\\\ slope = m\implies \cfrac{\stackrel{rise}{ y_2- y_1}}{\stackrel{run}{ x_2- x_1}}\implies \cfrac{8-(-7)}{-6-x}=\stackrel{\textit{slope}}{-\cfrac{15}{7}}\implies \cfrac{8+7}{-6-x}=-\cfrac{15}{7} \\\\\\ \cfrac{15}{-6-x}=-\cfrac{15}{7}\implies 105=(-6-x)(-15)\implies 105=90+15x \\\\\\ 15=15x\implies \cfrac{15}{15}=x\implies 1=x[/tex]
