Chapter 4 - Section 4.2 - Compound Inequalities - Exercise Set - Page 274: 77

See the explanation below.

Define intersection of two sets. The intersection of two sets is defined as two sets consists of numbers in common which refers to the solution of two sets or intersection of two sets. When the both sets does not contain any common number then it can be termed as empty set. The term intersection is denoted by symbol $ \cap$. Consider on example: {$11,12,13,14$} $\cap$ {$12,14,16,18$} solution: {$12,14$}