## Algebra 2 (1st Edition)

By using the slope formula, the slopes of the lines are: $m_1=\frac{y_2-y_1}{x_2-x_1}=\frac{7-(-2)}{2-(-1)}=\frac{9}{3}=3.$ $m_2=\frac{y_2-y_1}{x_2-x_1}=\frac{-6-(-3)}{3-(-6)}=\frac{-3}{9}=\frac{-1}{3}.$ Since $m_1m_2=-1$, they are perpendicular.