Chapter 1 - Introduction to Algebraic Expressions - 1.7 Multiplication and Division of Real Numbers - 1.7 Exercise Set - Page 58: 111

$-12$

The given expression, $ \dfrac{9}{5}\cdot\dfrac{-20}{3} $, simplifies to \begin{array}{l}\require{cancel} \dfrac{9(-20)}{5(3)} \\\\= \dfrac{\cancel{3}\cdot3\cdot\cancel{5}\cdot(-4)}{\cancel{5}(\cancel{3})} \\\\= 3(-4) \\\\= -12 .\end{array}