Answer: A) all real numbers
The domain is the set of all possible x inputs. The blue curve stretches on forever in both directions along the x axis. This means that we can plug in any x value we want, and get some y output. We don't have to worry about dividing by zero, or applying the square root of a negative number, so there are no restrictions on the domain. We can take the cube root of a negative number with no issues. For example, the cube root of -8 is -2.
