[tex]\bf \begin{array}{ccccccccc}
&&x_1&&y_1\\
% (a,b)
&J&(~{{ 4}} &,&{{ -4}}~)
\end{array}
\\\\\\
% slope = m
slope = {{ m}}\implies 4
\\\\\\
% point-slope intercept
\stackrel{\textit{point-slope form}}{y-{{ y_1}}={{ m}}(x-{{ x_1}})}\implies y-(-4)=4(x-4)\implies y+4=4x-16
\\\\\\
y=4x-16-4\implies y=4x-20[/tex]
