* Different Variables:
* Example: 3x and 5y (They have different variables)
* Different Exponents:
* Example: 2x² and 4x (They have the same variable but different exponents)
* Different Coefficients and Exponents:
* Example: 7x³ and 9y² (They have different variables and exponents)
* Different Variables and Exponents:
* Example: 10ab and 12a²b³ (They have different variables and exponents)
* Constants and Variables:
* Example: 8 and 2x (One is a constant, the other is a variable)
Remember: Like terms must have the same variable(s) and the same exponent(s) for each variable.