Final answer:
The domain of the function y = 2/3 + x is all real numbers.
Step-by-step explanation:
The domain of a function represents the set of all possible input values (x) for which the function is defined. In this case, the function is y = 2/3 + x. Since there are no restrictions or limitations on the input (x), the domain of this function is all real numbers or (-∞, +∞).