Given the function, f(x) = x, using 5 rectangles of equal width, find an approximation to the area between the-curve and the x-axis over the interval [3,9] if the heights of the rectangles are found by evaluating the function at the left endpoints, right endpoints, and midpoints of each subinterval created by a partition of the interval given. Using left endpoints, the approximate area is: Using right endpoints, the approximate area is: Using midpoints, the approximate area is: