well, let's first find the slope of "this" line hmmmmm what would that be?
[tex] \bf (\stackrel{x_1}{1}~,~\stackrel{y_1}{-6})\qquad
(\stackrel{x_2}{-2}~,~\stackrel{y_2}{6})
\\\\\\
slope = m\implies
\cfrac{\stackrel{rise}{ y_2- y_1}}{\stackrel{run}{ x_2- x_1}}\implies \cfrac{6-(-6)}{-2-1}\implies \cfrac{6+6}{-2-1}
\\\\\\
\cfrac{12}{-3}\implies -4 [/tex]
[tex] \bf \stackrel{\textit{perpendicular lines have \underline{negative reciprocal} slopes}}
{\stackrel{slope}{-4\implies -\cfrac{4}{1}}\qquad \qquad \qquad \stackrel{reciprocal}{-\cfrac{1}{4}}\qquad \stackrel{negative~reciprocal}{+\cfrac{1}{4}}}\implies \cfrac{1}{4} [/tex]
