[tex](\stackrel{x_1}{9}~,~\stackrel{y_1}{-9})\hspace{10em} \stackrel{slope}{m} ~=~ 4 \\\\\\ \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}{(-9)}=\stackrel{m}{ 4}(x-\stackrel{x_1}{9}) \implies y +9= 4 (x -9)[/tex]