Chapter 1 - Introduction to Algebraic Expressions - 1.7 Multiplication and Division of Real Numbers - 1.7 Exercise Set - Page 58: 89

$-\dfrac{5}{4}$

To find the reciprocal of a number, interchange the numerator and the denominator. Hence, the reciprocal of the given expression, $ -\dfrac{4}{5} $, is \begin{array}{l}\require{cancel} -\dfrac{5}{4} .\end{array}