Find the remainder if the polynomial f(x) = 3x^100 + 5x^87 - 4x^40 + 2x^21 - 6 divided by p(x) = x + 1

The thing is, I can't use synthetic OR long division BECAUSE I'd have a VERY VERY long equation (since you have to fill in the missing degrees: 99,98,97,96,95......etc).

How would you solve this?