Synthetic Division
p(x) / (x - x0) = q(x) + r / (x - x0) where r is the remainder.
p(x) and q(x) are represented as a list of coefficients with powers in descending order.
p(x) = a_n * x^n + a_(n-1) * x^(n-1) + … + a2 * x^2 + a1 * x + a0 l1 = [a_n, a_(n-1), … , a2, a1, a0]
q(x) is similar and is stored in l2.