1 point) The image below shows the graph of the function f (I). 1/0 4:0 Using what you know about the derivative function, answer the following (all intervals should be inside the bigger interval (-7, 7); do not include any points in your intervals outside of this set): a) When does f' (x) cross the r-axis? b) When is f'(x) 2 0? c) When is f'(x)