## Precalculus: Concepts Through Functions, A Unit Circle Approach to Trigonometry (3rd Edition)

$\dfrac{2}{3}$
By using the slope formula, $m=\dfrac{y_2-y_1}{x_2-x_1}=\dfrac{3-5}{-1-2}=\dfrac{-2}{-3}=\dfrac{2}{3}$