Chapter 1 - Introduction to Algebraic Expressions - 1.7 Multiplication and Division of Real Numbers - 1.7 Exercise Set - Page 58: 109

$-\dfrac{7}{4}$

The given expression, $ \dfrac{7}{8}\div\left( -\dfrac{1}{2} \right) $, simplifies to \begin{array}{l}\require{cancel} \dfrac{7}{8}\cdot\left( -\dfrac{2}{1} \right) \\\\= \dfrac{7(-2)}{8(1)} \\\\= \dfrac{-14}{8} \\\\= \dfrac{\cancel{2}\cdot(-7)}{\cancel{2}\cdot4} \\\\= \dfrac{-7}{4} \\\\= -\dfrac{7}{4} .\end{array}