Answer
The slope is undefined because the line is vertical.
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 $(-1,2)$ and $(-1,-2)$ to obtain:
$m=\dfrac{-2-2}{-1-(-1))}=\dfrac{-4}{0}$ which is undefined.
A line with an undefined slope is vertical.
Plot the points and connect them using a line.
