Which statement best describes how to determine whether f(x) = x4 – x3 is an even function? Determine whether (–x)4 – (–x)3 is equivalent to x4 – x3. Determine whether (–x4) – (–x3) is equivalent to x4 x3. Determine whether (–x)4 – (–x)3 is equivalent to –(x4 – x3). Determine whether (–x4) – (–x3) is equivalent to –(x4 x3).