## Algebra and Trigonometry 10th Edition

Slope of Line 1 : $m_1=\frac{y_2-y_1}{x_2-x_1}=\frac{-1-5}{-2-1}=\frac{-6}{-3}=2$ Slope of Line 1 : $m_2=\frac{y_2-y_1}{x_2-x_1}=\frac{3-(-5)}{1-5}=\frac{8}{-4}=-2$ Hence the lines are neither perpendicular as $m_1 * m_2 \ne -1$ nor parallel as $m_1\ne m_2$.