For the following exercises, graph the equations and shade the area of the region between the curves. Determine its area by integrating over the x-axis. 7. y = x2 and y = -x2 + 18x 8. y = _,y = 2, and x = 3 9. y = cos x and y = cos x on x = [-It, ] 10. y = ex, y = e2x-1, and x = 0