Assuming that p + q > 0, the cubic polynomial x + 3px + 2q has a root r(p, q) = -q+q +p + -9-q+p. Write a Python function r(p, q) which returns r(p, q). You can assume that the inputs p and q are real numbers such that q +p > 0. Your function must produce the correct result for any such p and q.