Answer
$m=0$
Refer to the graph below.
Work Step by Step
The slope of the line can be determined by the equation:
$m=\dfrac{y_2-y_1}{x_2-x_1}$
where $(x_1, y_1)$ and $(x_2, y_2)$ are two given points on the line.
Here, we can substitute the coordinates of the points $(4,2)$ and $(-5,2)$ to obtain:
$m=\dfrac{2-2}{-5-4)}=\dfrac{0}{-9}=0$
Plot the points and connect them using a line.