Width = (b - a)/n = (8 - 0)/4 = 2 2(f(0) + f(2) + f(4) + f(6)) 2(-1 - 2.5 - 1.5 - 0.5) 2(-5.5) -11 is my answer c, -11? the question says four subintervals, so i used f(0), f(2), f(4), and f(6). i want to make sure that i am not supposed to be using f(8), because f(8) would give me a final answer of d. -13.5