Consider the function f(x) = 12x* + 75x4 - 120x3+ 3. f(x) has inflection points at (reading from left to right) x = D, E, and F where D is and E is and F is For each of the following intervals, tell whether f(@ ) is concave up or concave down. (-00, D): Select an answer v (D, E): Select an answer v (E, F): Select an answer v (F, 00): Select an answer v