What does it mean to simplify an expression?

Simplifying an expression means to write it in a simpler form, reducing complexity while maintaining the same mathematical value. This often involves combining like terms, eliminating unnecessary parentheses, or using properties of operations to rewrite the expression in a more straightforward way. For example, transforming ( 2x + 3x ) into ( 5x ) is a simplification, as it expresses the quantity more concisely. The goal is to make the expression easier to work with or understand, making option C the correct choice.