Answer
$\dfrac{2}{9}$
Work Step by Step
RECALL:
$\dfrac{a}{b} \div \dfrac{c}{d} = \dfrac{a}{b} \times \dfrac{d}{c}$
Use the rule above to obtain:
$=\dfrac{-4}{n} \times \dfrac{n}{-18}$
Cancel out the common factors, and then multiply to obtain:
$\require{cancel}
\\=\dfrac{\cancel{-4}2}{\cancel{n}} \times \dfrac{\cancel{n}}{\cancel{-18}9}
\\=\dfrac{2}{9}$
