3. Let f be continuous and non-negative on the interval [a, b]. The area of the region bound by the graph of f, the x-axis, and the vertical lines x-a and x=b using Riemann Sum is: Area = limf(c)Ax, where c, is the right end point and Ax = C-C. Using this definition and an i=1 appropriate formula for c,, find the area if f(x) = 3x and interval is [0, 8]. Show complete work.