[tex]\bf \begin{array}{ccccccccc}
&&x_1&&y_1&&x_2&&y_2\\
&&(~ -8 &,& 7~)
&&(~ -9 &,& -5~)
\end{array}
\\\\\\
slope = m\implies
\cfrac{\stackrel{rise}{ y_2- y_1}}{\stackrel{run}{ x_2- x_1}}\implies \cfrac{-5-7}{-9-(-8)}\implies \cfrac{-5-7}{-9+8}\implies 12
\\\\\\
\stackrel{\textit{point-slope form}}{y- y_1= m(x- x_1)}\implies y-7=12[x-(-8)]\implies y-7=12(x+8)
\\\\\\
y-7=12x+96\implies -12x+y=103[/tex]