Which statement best describes how to determine whether f(x) = x4 – x3 is an even function?

To test whether a function is even, substitute −x for x and check whether f(−x) = f(x). Here, f(−x) = (−x)⁴ − (−x)³, so the needed comparison is with x⁴ − x³. That is the test described by choice A. In fact, these expressions are not equivalent because f(−x) = x⁴ + x³, so the function is not even.

AI-written and checked against the verified answer.