An algebraic expression is a combination of numbers, variables, and mathematical operations. For example, in the expression 3x + 5, x is a variable that can represent any number, while 3 and 5 are constants. Algebraic expressions can be used to model real-world situations, such as calculating the total cost of items or determining distances. These expressions can be simplified or manipulated using various rules of algebra. For instance, you can combine like terms or apply the distributive property. Understanding algebraic expressions is essential for solving equations and tackling more complex mathematical problems in fields like science, engineering, and finance.