Consider the function f(x) = 12x' + 45x4 - 80x3 + 2. 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, oo): Select an answer v Question Help: Video