Answer
$-9c^{4}d^{2}$
Work Step by Step
Using the laws of exponents, the given expression, $
\dfrac{-18c^9d^3}{2c^5d}
,$ simplifies to
\begin{array}{l}\require{cancel}
\dfrac{\cancel{2}\cdot(-9)c^{9-5}d^{3-1}}{\cancel{2}}
\\\\=
-9c^{4}d^{2}
.\end{array}