[tex]\bf \begin{array}{lllll}
&x_1&y_1&x_2&y_2\\
% (a,b)
&({{ -6}}\quad ,&{{ 19}})\quad
% (c,d)
&({{ -15}}\quad ,&{{ 28}})
\end{array}
\\\\\\
% slope = m
slope = {{ m}}= \cfrac{rise}{run} \implies
\cfrac{{{ y_2}}-{{ y_1}}}{{{ x_2}}-{{ x_1}}}\implies \cfrac{28-19}{-15-(-6)}\implies \cfrac{28-19}{-15+6}
\\\\\\
\cfrac{9}{-9}\implies -1
\\\\\\
% point-slope intercept
y-{{ y_1}}={{ m}}(x-{{ x_1}})\implies y-19=-1(x-(-6))\\
\left. \qquad \right. \uparrow\\
\textit{point-slope form}
\\\\\\
y-19=-(x+6)[/tex]
