Consider the function below. f(x) =    x2 + 3  − x (a) Find the vertical asymptote(s). (Enter your answers as a comma-separated list. If an answer does not exist, enter DNE.)x =     Find the horizontal asymptote(s). (Enter your answers as a comma-separated list. If an answer does not exist, enter DNE.)y =     (b) Find the interval where the function is decreasing. (Enter your answer in interval notation.)     (c) Find the interval where the function is concave up. (Enter your answer in interval notation.)     (d) Use this information to sketch the graph of f. (Do this on paper. Your instructor may ask you to turn in this graph.)