Chapter 6 - Algebra: Equations and Inequalities - 6.4 Linear Inequalities in One Variable - Concept and Vocabulary Check - Page 383: 3

$\left\{x| a \lt x \le b\right\}$

RECALL: The solution set $\left\{x| a \lt x \le b\right\}$ includes all real numbers $x$ that are greater than $a$ and less than or equal to $b$. Thus, the missing expression in the given statement is: $\left\{x| a \lt x \le b\right\}$