For the function below, nd a] the critical numbers; b) the open intervals where the function is increasing; and c] the open intervals where it is decreasing. rrx)=-.lx2+1o ( ..... all Find the critical numberis]. Select the correct choice below and, it necessary. ll in the answer box to complete your choice. 0 A- The critical numberis) isfare E. (Type an integer or a simplied fraction. Use a comma to separate answers as needed.) 0 B. There are no critical numbers. Determine the location of each local extremum of the function. f(x) = -x*+ 9x- - 24x - 1 What is/are the local minimum/minima? Select the correct choice below and, if necessary, fill in the answer box to complete your choice. O A. The local minimum/minima is/are at x =. (Use a comma to separate answers as needed. Type integers or simplified fractions.) O B. The function has no local minimum.