Answer
$m=-2$
Work Step by Step
Using $m=\dfrac{y_1-y_2}{x_1-x_2}$ or the Slope Formula, the slope of the line passing through the given points $(
5,8
)$ and $(
3,12
)$ is
\begin{array}{l}\require{cancel}
m=\dfrac{8-12}{5-3}
\\\\
m=\dfrac{-4}{2}
\\\\
m=-2
.\end{array}