Answer
$m=0$
Work Step by Step
Using $m=\dfrac{y_1-y_2}{x_1-x_2}$ or the Slope Formula, then the slope, $m$, of the line containing the given points, $(
6,-3
)\text{ and } (
2,-3
)$, is
\begin{array}{l}
m=\dfrac{-3-(-3)}{6-2}
\\\\
m=\dfrac{-3+3}{6-2}
\\\\
m=\dfrac{0}{4}
\\\\
m=0
.\end{array}