Suppose that f(x) = fe^x/5e^x+7

Suppose that f(ac) = 5ex 5ex + 7 (A) Find all critical values of f. If there are no critical values, enter None. If there are more than one, enter them separated by commas. Critical value(s) = (B) Use interval notation to indicate where f(x) is concave up. Concave up: (C) Use interval notation to indicate where f(x) is concave down. Concave down: (D) Find all inflection points of f. If there are no inflection points, enter None. If there are more than one, enter them separated by commas. Inflection point(s) at x =