1. The figure below shows the graph of f : the derivative of the function f, on the closed interval from x = -2 to x = 6. The graph of the derivative has horizontal tangent lines at x = 2 and x = 4. (6, 4) (2,0) (3. 0) (0, -2) (4, -2.5) (-2, -3) Find the x-value where f attains its absolute maximum value on the closed interval from x = -2 to x = 6. Justify your answer. (10 points)