[tex]\bf (\stackrel{x_1}{3}~,~\stackrel{y_1}{-9})~\hspace{10em} slope = m\implies 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-(-9)=4(x-3) \\\\\\ y+9=4x-12\implies y=4x-21[/tex]
