Chapter 6 - Review - Page 404: 63

$x=6$

Multiplying both sides by the $LCD= 3x $, the value of the variable that satisfies the given equation, $ \dfrac{3}{x}+\dfrac{1}{3}=\dfrac{5}{x} ,$ is \begin{array}{l}\require{cancel} 3(3)+x(1)=3(5) \\\\ 9+x=15 \\\\ x=15-9 \\\\ x=6 .\end{array}