Answer
$(x-1)(x+1)$
Work Step by Step
By using the difference of two squares $x^2-a^2=(x-a)(x+a)$, we have
$$
x^2 - 1=(x-1)(x+1)
.$$
You can help us out by revising, improving and updating this answer.
Update this answerAfter you claim an answer you’ll have 24 hours to send in a draft. An editor will review the submission and either publish your submission or provide feedback.