Query about Question 1 from "GRE Mini Exam #9" [1431]

Link: https://www.gregmat.com/quizzes/quiz/gre-mini-exam-9-loyt (Question 1)


Hi all,

Shouldn’t the question to this be x is a positive odd integer? Am I mistaken in believing that if x is a negative odd integer, say -1, x^3 - x would then equal -2, in which case the two quantities’ remainders would vary?