Chapter 3 - Equations and Problem Solving - Chapter 3 Test - Page 139: 12

$x=\dfrac{y+8}{2}$

Using the properties of equality, in terms of $ x ,$ the given equation, $ y=2(x-4) ,$ is equivalent to \begin{array}{l}\require{cancel} y=2x-8 \\\\ y+8=2x \\\\ \dfrac{y+8}{2}=x \\\\ x=\dfrac{y+8}{2} .\end{array}