Algebraic expressions consist of numbers and variables combined through operations such as addition and subtraction. The individual parts of an expression separated by plus or minus signs are called terms. For example, in the expression 2x + 5, the terms are 2x and 5.
Like terms are terms that contain the exact same variables raised to the same exponents. The order of variables does not affect whether terms are like terms because multiplication is commutative. For instance, 4x² and 7x² are like terms since both have the variable x raised to the power of 2. Similarly, 2ab and 8ba are like terms because they contain the same variables a and b, each raised to the first power (implied exponent 1). Another example is 5x²yz and -10x²yz, where the variables x, y, and z match exactly with the same exponents.
It is important to note that the coefficients (numerical factors) of terms do not determine whether terms are like terms. Only the variables and their exponents matter.
Unlike terms differ either in their variables or in the exponents of those variables. For example, 4x² and 7x³ are not like terms because the exponents of x differ (2 versus 3). Likewise, 2a and 2ba are not like terms because the second term contains an additional variable b. Another example is 5x²yz and -10xy²z, which are unlike terms since the exponents of x and y differ between the two terms.
Combining like terms is a fundamental skill in algebra. This process involves adding or subtracting the coefficients of like terms while keeping the variable part unchanged. For example, combining 4x² + 7x² results in 11x² by adding the coefficients 4 and 7. Similarly, 2ab + 8ba can be combined as 10ab after recognizing the terms as like terms and adding their coefficients.
It is crucial to avoid combining unlike terms, as their variable parts differ. For instance, 5x²yz - 10xy²z cannot be combined because the exponents of x and y differ, making them unlike terms.
Understanding how to identify terms, distinguish like terms from unlike terms, and correctly combine like terms lays the foundation for simplifying algebraic expressions and solving equations efficiently.