The begging is not needed and offensive.
You have had some input on question 16 in another thread, so I'll give you an idea of where to start and you can let us know how you did with it.
As in Q16 set up a Free-Body-Diagram (or a force diagram, whatever your instructor may call it.) What you are looking for is a tension in the wire such that m2 has no acceleration on it. That means that m1 has no acceleration either. So set a = 0 in your equations and see what comes up.