Chapter 10 - Exponents and Radicals - 10.1 Radical Expressions and Functions - 10.1 Exercise Set - Page 635: 107

$f\left( \dfrac{1}{3} \right)=0$

Substituting $x=\dfrac{1}{3}$ in $f(x)=3x-1,$ then \begin{array}{l}\require{cancel} f(x)=3x-1 \\\\ f\left( \dfrac{1}{3} \right)=3\left( \dfrac{1}{3} \right)-1 \\\\ f\left( \dfrac{1}{3} \right)=1-1 \\\\ f\left( \dfrac{1}{3} \right)=0 .\end{array}