Donna does a weekly exercise program consisting of cardiovascular work and weight training. Each week, she exercises for at least 6 hours. She spends at most 9 hours doing cardiovascular work. She spends at most 3 hours on weight training. Let x denote the time (in hours) that Donna spends doing cardiovascular work. Let y denote the time (in hours) that she spends on weight training. Shade the region corresponding to all values of x and y that satisfy these requirements.