1. The problem asks to identify which of the given items are expressions. 2. An expression is a mathematical phrase that can contain numbers, variables, and operation symbols but does not include an equality or inequality sign. 3. Let's analyze each item: - $x - 5 = 0$: This is an equation because it has an equality sign. - $2 > 5x - 8$: This is an inequality, not an expression. - $7x + 3$: This is an expression because it contains variables and numbers combined with operations but no equality or inequality. - $4x + 4 = 20 + x$: This is an equation. - $2a$: This is an expression. 4. Therefore, the expressions are $7x + 3$ and $2a$. Final answer: $7x + 3$ and $2a$ are expressions.