A highway engineer develops a formula to estimate the number of cars that can safely travel a particular highway at a given speed. She finds that the number N of cars that can pass a given point per minute is modeled by the function N(x) = 88x/ 17 + 17(x/20)^2. Required:
Graph the function in the viewing rectangle [0, 100] by [0, 60]. If the number of cars that pass by the given point is greater than 40, at what range of speeds can the cars travel?