Answer
See below:
Work Step by Step
The provided equation in polar form is $ r=-3\csc \theta $
As $ x=r\cos \theta \ \text{ and }\ y=r\sin \theta $,
$\begin{align}
& r=-3\csc \theta \\
& r=\frac{-3}{\sin \theta } \\
& r\sin \theta =-3 \\
& y=-3
\end{align}$
