According to the Polynomial Remainder Theorem, if we divide a polynomial P(x) by a binomial (<em>x</em> - <em>a</em>), then the remainder of the operation will be given by P(a).
Our polynomial is:
And we want to find the remainder when it's divided by the binomial:
We can rewrite our divisor as (<em>x</em> - (-1)). Hence, <em>a</em> = -1.