Hi! I'm in Physics II this semester, and I have been stuck on this attached electric potential problem. I've tried several different ways of working

Hi! I'm in Physics II this semester, and I have been stuck on this attached electric potential problem. I've tried several different ways of working the problem, but none of them produce the correct solution. I think one of the parts of the problem that I may be struggling with is how to determine the force produced by each charge on point A by using a method similar to using components of vectors. Thanks so very much for your help! It is much appreciated!