Approximate the area under the graph of f(x) and above the x-axis using left endpoints with n = 4 rectangles. f(x) = -+5, from x =1 to x=9. Submit a complete written solution for this problem. X 1 2 3 4 5 6 7 8 9 10 The area, approximated using the left endpoints, is (Round to two decimal places as needed.)