What you need to do is to understand the basis of one of these theoretical perspectives and then try to apply it to the issue of poverty.
For example, functionalism holds that everything about society makes society work better. So how would poverty do that? The idea here is that the fear of poverty and the knowledge that poverty could happen to us is good for us. Specifically, it makes us work harder and act in better ways so as to avoid it. If poverty did not exist, society would be worse off because people would not work hard and act responsibly because they would not need to fear poverty.