Chapter 2 - Equations, Inequalities, and Problem Solving - 2.1 Solving Equations - 2.1 Exercise Set - Page 87: 63

$r=1$

Multiplying both sides by $ -\dfrac{5}{3} $, then the solution to the given equation, $ -\dfrac{3}{5}r=-\dfrac{3}{5} $, is \begin{array}{l}\require{cancel} \left(-\dfrac{5}{3}\right)\left(-\dfrac{3}{5}r\right)=\left(-\dfrac{3}{5}\right)\left(-\dfrac{5}{3}\right) \\\\ \dfrac{15}{15}r=\dfrac{15}{15} \\\\ r=1 .\end{array}