Find the area of the regions in Exercises 7-13. 7. Between the parabola y = 4 - x and the x-axis. 8. Between y = x2 - 9 and the x-axis. 9. Under one arch of y = sin a and above the x-axis. 10. Between the line y = 1 and one arch of y = sin 0. 11. Between y = -x + 5x - 4 and the x-axis, 0