Chapter 2 Linear Equations and Functions - 2.2 Find Slope and Rate of Change - 2.2 Exercises - Skill Practice - Page 86: 21

perpendicular

By using the slope formula, the slopes of the lines are: $m_1=\frac{y_2-y_1}{x_2-x_1}=\frac{8-2}{5-7}=\frac{6}{-2}=-3.$ $m_2=\frac{y_2-y_1}{x_2-x_1}=\frac{-2-(-1)}{-7-(-4)}=\frac{-1}{-3}=\frac{1}{3}.$ Since $m_1m_2=-1$, they are perpendicular.