looking at the line on the graph, we can use a couple of point off of it, to get the slope, hmm the line is passing through -4,4 and 0,1, so let's use those,
[tex]\bf \begin{array}{ccccccccc}
&&x_1&&y_1&&x_2&&y_2\\
% (a,b)
&&(~ -4 &,& 4~)
% (c,d)
&&(~ 0 &,& 1~)
\end{array}
\\\\\\
% slope = m
slope = m\implies
\cfrac{\stackrel{rise}{ y_2- y_1}}{\stackrel{run}{ x_2- x_1}}\implies \cfrac{1-4}{0-(-4)}\implies \cfrac{1-4}{0+4}\implies \cfrac{-3}{4}[/tex]