Let f(x) = 9x-6x3 + 23x + 25. Use Descartes' Rule of Signs to answer the following questions. (a) List the possible number of positive real zeros (counting multiplicities) of f(x): (b) List the possible number of negative real zeros (counting multiplicities) of f(x): (c) May anything definitive be said about the exact number of positive real zeros? Select an answer (d) May anything definitive be said about the exact number of negative real zeros? Select an answer Select an answer There are no negative real zeros. There are exactly two real negative zeros. There is exactly one negative real zero. No conclusion may be made about the exact number of negative real zeros.