Chapter 8 - Coordinate Geometry and Linear Systems - 8.3 - Slope of a Line - Problem Set 8.3 - Page 349: 10

$m=\dfrac{3}{5}$

Using $m=\dfrac{y_1-y_2}{x_1-x_2}$, the slope of the line determined by the given points, $( 5,-3 ) \text{ and } ( -5,-9 ),$ is \begin{array}{l}\require{cancel} m=\dfrac{-3-(-9)}{5-(-5)} \\\\ m=\dfrac{-3+9}{5+5} \\\\ m=\dfrac{6}{10} \\\\ m=\dfrac{\cancel{2}\cdot3}{\cancel{2}\cdot5} \\\\ m=\dfrac{3}{5} .\end{array}