Answer
$\dfrac{2}{3}$
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:
$=\dfrac{-34}{n} \times \dfrac{n}{-51}
\\=\dfrac{-17(2)}{n} \times \dfrac{n}{-17(3)}$
Cancel common factors then multiply to have:
$\require{cancel}
\\=\dfrac{\cancel{-17}(2)}{\cancel{n}} \times \dfrac{\cancel{n}}{\cancel{-17}(3)}
\\=\dfrac{2}{3}$
