a Estimate the area under the graph of f x 5 x from x 0 to x 4 using four approximating rectangles and right endpoints Round your answers to four decimal places R4 Sketch the graph and the rectangles y 10 8 6 2 y 10 8 6 4 f x 5 x 1 f x 5 x WebAssign Plot 4 y 10 8 2 f x 5 x 1 2 3 y 10 8 f x 5 x At 6 X