This is a good question that is not easily answered. If it was easy, then the problem would likely already be solved. One approach is to reduce the amount of guns through various laws. Proponents would mention that with less guns on the streets, it likely would lead to less violence. However, many would argue that the guns can easily come from out of state for instance. Also, there's the second amendment which is important to a person's civil rights.
Another approach could be through education programs and job creation. If more people are pulled out of poverty, then they might have less reason to fight. This might be a more effective approach compared to gun control mentioned earlier. Though in my opinion, perhaps both tools are needed on some level. Of course I'm not advocating the outright ban of guns or anything. Instead, there should be more thorough background checks and loopholes should be closed up to avoid mentally ill people from able to access guns. In addition, people convicted of domestic abuse cases shouldn't be able to access guns (or at the very least should follow a strict process to prove they have been rehabilitated before they can acess guns).
Yet another approach is to improve healthcare. Specifically mental healthcare. Many plans only provide coverage for things like checkups and physicals, but often leave out things like therapy. I think the trend is starting to reverse course and mental health is slowly starting to be considered as part of overall wellness. Though there needs to be more effort put into helping treat mental illness and diagnosing it. This would hopefully prevent future gun tragedies.
Once again, there's no single magical solution to fix this complicated problem. It has been going on for quite a while, and it's not unique to the city of Philadelphia. Other big cities have crime as well of course. It's the unfortunate part of what it means to live in a city of that size. Though it might be possible to reduce crime if resources are allocated properly and spent efficiently. One last thing to mention is housing which I suppose is strongly related to the jobs thing I mentioned earlier. If housing could be more affordable, then it could reduce stress/tension that often leads to violence. This can be applied to easing traffic congestion as well.
As with many governments, red tape gets in the way of a lot of what is discussed from being implemented. Many people have their own view of what would solve this problem. Disagreements clog up process. So perhaps part of the overall should involve a process to streamline the changes so they are more efficient, rather than take years to implement.
Side note: I didn't have a source because I'm just writing from what I know about the matter. Also, when writing to your teacher be sure to use your own words of course.