[tex](\stackrel{x_1}{4}~,~\stackrel{y_1}{-7})\hspace{10em} \stackrel{slope}{m} ~=~ -5 \\\\\\ \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-\stackrel{y_1}{(-7)}=\stackrel{m}{-5}(x-\stackrel{x_1}{4}) \\\\\\ y+7=-5x+20\implies y=-5x+13[/tex]