Please see below.
Work Step by Step
To plot the point $(r, \theta )=(-3, -\pi )$, begin with the $-\pi$ angle. Because $-\pi$ is a negative angle, draw $\theta = -\pi$ clockwise from the polar axis. Now consider $r=-3$. Because $r \lt 0$, plot the point by going out three units along the ray opposite the terminal side of $\theta$.