In algebra, simplifying an expression involves reducing a complex expression into a simpler form by combining like terms. A term is defined as a part of an expression separated by plus or minus signs. For example, in the expression 5 - x + 3y + y, the terms are 5, -x, 3y, and y. Terms can be numbers, variables, or combinations of both. Like terms are those that share the same variable and exponent, such as 3y and y, which can be combined to simplify the expression.

To simplify an algebraic expression, follow a systematic approach. First, distribute any constants or variables outside parentheses. For instance, in the expression 2x + 3 + 4(x + 2), distributing the 4 gives 4x + 8. The expression now reads 2x + 3 + 4x + 8.

Next, group like terms together. This means rearranging the expression to place similar terms next to each other. In our example, we can write it as 2x + 4x + 3 + 8. This step helps in visualizing which terms can be combined.

The final step is to combine the like terms by adding or subtracting them. For the expression 2x + 4x + 3 + 8, we can combine 2x and 4x to get 6x, and combine 3 and 8 to get 11. Thus, the simplified expression is 6x + 11. This process illustrates how a complex expression can be reduced to a simpler form with fewer terms, enhancing clarity and ease of use in further calculations.