Chapter 1 - Introduction to Algebraic Expressions - 1.8 Exponential Notation and Order of Operations - 1.8 Exercise Set - Page 67: 77

$\dfrac{5}{6}$

Substituting $ x $ with $ 3 $ in the given expression, $ 45\div3^2x(x-1) $, then, \begin{array}{l}\require{cancel} 45\div3^2(3)(3-1) \\\\= 45\div9(3)(2) \\\\= 45\div27(2) \\\\= 45\div54 \\\\= \dfrac{\cancel{9}\cdot5}{\cancel{9}\cdot6} \\\\= \dfrac{5}{6} .\end{array}