Consider the function f(x) 12x5 +30x¹300x³ +5. 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(x) is concave up or concave down. (-[infinity], D): [Select an answer (D, E): Select an answer (E, F): Select an answer (F, [infinity]): Select an answer ✓