Chapter 1, Equations and Inequalities - 1.7 Solve Absolute Value Equations and Inequalities - 1.7 Exercises - Skill Practice - Page 55: 30

$$x=-28\quad \mathrm{or}\quad \:x=52$$

Since the value inside the absolute value can be positive or negative and get the same number, we must consider both options. Doing this, we find: $$0.25x-3=-10\quad \mathrm{or}\quad \:0.25x-3=10 \\ x=-28\quad \mathrm{or}\quad \:x=52$$