Equivalent expressions are mathematical phrases that represent the same value, even if they look different. For example, the expressions 3 + 2 and 5 are equivalent because they both equal 5. This concept is important in algebra, as it allows us to simplify expressions and solve equations more easily. To determine if two expressions are equivalent, you can use various methods, such as simplifying both expressions or substituting values for the variables. Understanding equivalent expressions helps in solving problems and manipulating algebraic equations, making it a fundamental skill in mathematics.