Answer
$\dfrac{1}{5}$
Work Step by Step
Convert the mixed number to an improper fraction:
$=\dfrac{-3}{7} \div \dfrac{-(7 \cdot 2 + 1)}{7}
\\=\dfrac{-3}{7} \div \dfrac{-15}{7}$
Use the rule $\frac{a}{b} \div \frac{c}{d} = \frac{a}{b} \times \frac{d}{c}$:
$=\dfrac{-3}{7} \times \dfrac{7}{-15}$
Cancel common factors and then multiply:
$\require{cancel}
=\dfrac{\cancel{-3}1}{\cancel{7}} \times \dfrac{\cancel{7}}{\cancel{-15}5}
\\=\dfrac{1}{5}$
