Chapter 2 - Equations, Inequalities, and Problem Solving - 2.2 Using the Principles Together - 2.2 Exercise Set - Page 94: 22

$t=-8 $

Using the properties of equality, the solution to the given equation, $ -39=1+5t $, is \begin{array}{l} -39-1=5t \\\\ -40=5t \\\\ \dfrac{-40}{5}=t \\\\ t=-8 .\end{array} Checking: \begin{array}{l} -39=1+5(-8) \\\\ -39=1-40 \\\\ -39=-39 \text{ (TRUE)} .\end{array} Hence, the solution is $ t=-8 .$