For the function below find a the critical numbers b the open intervals where the function is increasing and c the open intervals where it is decreasing f x 2x 3x 36x 18 a Find the critical number s Select the correct answer below and if necessary fill in the answer box within your choice OA The critical number s is are Type an integer or a simplified fraction Use a comma to separate answers as needed OB There are no critical numbers b List any interval s on which the function is increasing Select the correct answer below and if necessary fill in the answer box within your choice OA The function is increasing on the interval s Type your answer in interval notation Use a comma to separate answers as needed OB The function is never increasing c List any interval s on which the function is decreasing Select the correct answer below and if necessary fill in the answer box within your choice OA The function is decreasing on the interval s Type your answer in interval notation Use a comma to separate answers as needed OB The function is never decreasing