Answer
$m=\dfrac{5}{4}$
Work Step by Step
Using $m=\dfrac{y_1-y_2}{x_1-x_2}$ or the Slope Formula, then the slope of the line containing the given points, $
(1,3) \text{ and }
(5,8)
$, is
\begin{array}{l}
m=\dfrac{3-8}{1-5}
\\\\
m=\dfrac{-5}{-4}
\\\\
m=\dfrac{5}{4}
.\end{array}