The pair that contains like terms is (4x², 3x²) because both terms have the variable x raised to the same power, making them combinable in algebraic expressions.
The question "Which of the following pairs contains like terms?" pertains to the concept of combining terms in algebra. In algebra, like terms are terms that have exactly the same variable parts, which means they have the same base and exponent. For example, 4x² and 3x² are like terms because they both contain the variable x raised to the second power. Therefore, the pair (4x², 3x²) contains like terms. Other pairs offered in the options such as (4x⁴, 3x³), (3x, 3x), and (4, 4x³) do not contain like terms because their variables do not match in terms of base and exponent.