For f(x) = 2x# - 16x2+ 8 find the following. (A) f' (x ) (B) The slope of the graph of fat x = - 1 (C) The equation of the tangent line at x = - 1 (D) The value(s) of x where the tangent line is horizontal (A ) f' (x) = (B) At x = - 1, the slope of the graph of f is (C) At x = - 1, the equation of the tangent line is y = (D) The tangent line is horizontal at x = (Use a comma to separate answers as needed.)