Chapter 4 - Section 4.2 - Compound Inequalities - Exercise Set - Page 274: 81

See the definition below.

Define union of two sets. The union of two sets is defined as two sets consists of numbers which are not in common which refers to the solution of two sets or union of two sets. The term intersection is denoted by symbol $ \cup$. Consider on example: {$11,12,13,14$} $\cup$ {$12,14,16,18$} solution: {$11,12,13,14,16,18$}