[tex]\bf \stackrel{\textit{perpendicular lines have \underline{negative reciprocal} slopes}}
{\stackrel{slope}{\cfrac{1}{8}}\qquad \qquad \qquad \stackrel{reciprocal}{\cfrac{8}{1}}\qquad \stackrel{negative~reciprocal}{-\cfrac{8}{1}}\implies -8}[/tex]
