this integral appeared on an online assignment, but im really having troubles figuring out the domain region D on this. I could simply use the upper and lower limits to sketch the domain D. However, the '7y' component is ticking me off, why cant dy vary from 7x to 7 for example??? i need to know this because i need to reverse the order of integration to dydx and to do so, i need to learn how to set up the limits for the new iteration.