Final answer:
No, x² is not an onto function on real numbers.
Step-by-step explanation:
No. An onto function, also known as a surjective function, is a function where every element in the codomain is mapped onto by at least one element in the domain. In the case of the function f(x) = x², the function is not onto on the set of real numbers. This is because there are negative numbers in the codomain of real numbers that do not have a corresponding element in the domain whose square is equal to that negative number.