Answer
$m=-1.5$
See the graph below.
Work Step by Step
The slope of the line that passes throught two points $(x_1, y_1)$ and $(x_2, y_2)$ can be found using the formula:
$m=\dfrac{y_2-y_1}{x_2-x_1}$
Thus, the slope of the line passing through the two given points is:
$m=\dfrac{0-3}{4-2}=\dfrac{-3}{2}=-1.5$
To graph, plot both points then connect them using a straight line.
Refer to the graph above.