now, bear in mind that, when the y-axis gets intercepted, x = 0, therefore 0,3 is really the y-intercept.
and when the x-axis gets intercepted, y = 0, therefore 4,0 is the x-intercept, thus we will use this one in the point-slope form then.
[tex]\bf \begin{array}{lllll}
&x_1&y_1&x_2&y_2\\
% (a,b)
&({{ 0}}\quad ,&{{ 3}})\quad
% (c,d)
&({{ 4}}\quad ,&{{ 0}})
\end{array}
\\\\\\
% slope = m
slope = {{ m}}= \cfrac{rise}{run} \implies
\cfrac{{{ y_2}}-{{ y_1}}}{{{ x_2}}-{{ x_1}}}\implies \cfrac{0-3}{4-0}\implies -\cfrac{3}{4}
\\\\\\
% point-slope intercept
\stackrel{\textit{point-slope form}}{y-{{ y_1}}={{ m}}(x-{{ x_1}})}\implies y-0=-\cfrac{3}{4}(x-4)[/tex]
