[tex]\bf (\stackrel{x_1}{-15}~,~\stackrel{y_1}{0})\qquad (\stackrel{x_2}{-9}~,~\stackrel{y_2}{12}) \\\\\\ slope = m\implies \cfrac{\stackrel{rise}{ y_2- y_1}}{\stackrel{run}{ x_2- x_1}}\implies \cfrac{12-0}{-9-(-15)}\implies \cfrac{12-0}{-9+15}\implies \cfrac{12}{6}\implies 2 \\\\\\ \begin{array}{|c|ll} \cline{1-1} \textit{point-slope form}\\ \cline{1-1} \\ y-y_1=m(x-x_1) \\\\ \cline{1-1} \end{array}\implies y-0=2[x-(-15)] \\\\\\ y=2(x+15)\implies y=2x+30[/tex]
