10. FLOODS The number of feet a stream is above or below its flood level in a town can be modeled by Ax) =4x3-22x2+ 30x, where x is the number of days since a storm hit the area. a. Use Descartes' Rule of Signs to describe the possible real zeros of the function. O possible negative roots 2 possible Positive roots b. Determine an interval in which all real zeros of the function must lie. Then find the real zero(s)