Chapter 2 - Equations, Inequalities, and Problem Solving - 2.2 Using the Principles Together - 2.2 Exercise Set - Page 94: 26

$x=15$

Using the properties of equality, the solution to the given equation, $ -7x-24=-129 $, is \begin{array}{l} -7x=-129+24 \\\\ -7x=-105 \\\\ x=\dfrac{-105}{-7} \\\\ x=15 .\end{array} Checking: \begin{array}{l} -7(15)-24=-129 \\\\ -105-24=-129 \\\\ -129=-129 \text{ (TRUE)} .\end{array} Hence, the solution is $ x=15 .$