## Elementary Algebra

$m=1$
Using $m=\dfrac{y_1-y_2}{x_1-x_2}$, the slope of the line determined by the given points, $( -1,10 ) \text{ and } ( -9,2 ),$ is \begin{array}{l}\require{cancel} m=\dfrac{10-2}{-1-(-9)} \\\\ m=\dfrac{10-2}{-1+9} \\\\ m=\dfrac{8}{8} \\\\ m=1 .\end{array}