Chapter 1 - 1.7 - Linear Inequalities in One Variable - 1.7 Exercises - Page 138: 79

$|x-7|\geq3$

$|u|\lt a~↔~-a\lt u\lt a$ $|u|\leq a~↔~-a\leq u\leq a$ $|u|\gt a~↔~u\lt-a~or~u\gt a$ $|u|\geq a~↔~u\leq-a~or~u\geq a$ $x\leq4$ or $x\geq10$ $x-7\leq4-7$ or $x-7\geq10-7$ $x-7\leq-3$ or $x-7\geq3$ $|x-7|\geq3$