Chapter 5 Polynomials and Polynomial Functions - 5.3 Add, Subtract, and Multiply Polynomials - 5.3 Exercises - Skill Practice - Page 349: 1

Like terms

Recall, like terms must (1) be raised to the same power and (2) consist of the same variable (i.e. x and y are not like terms). It is also important to note that numbers are all like terms with each other when not multiplied by anything.