[tex]\bf \begin{array}{ccccccccc}
&&x_1&&y_1\\
% (a,b)
&&(~ 12 &,& 3~)
\end{array}
\\\\\\
% slope = m
slope = m\implies \cfrac{1}{4}
\\\\\\
% point-slope intercept
\stackrel{\textit{point-slope form}}{y- y_1= m(x- x_1)}\implies y-3=\cfrac{1}{4}(x-12)
\\\\\\
y-3=\cfrac{1}{4}x-3
\implies
y=\cfrac{1}{4}x[/tex]
