(A) Estimate the area under the graph of f (20) = 223 +4 from x = -1 to x = 5, first using 6 approximationg rectangles and right endpoints, and then improving your estimate using 12 approximationg rectangles and right endpoints. 6 Rectangles = 12 Rectangles = (B) Repeat part (A) using left endpoints. 6 Rectangles = 12 Rectangles = (C) Repeat part (A) using midpoints. 6 Rectangles = 12 Rectangles =