1. The problem statement, all variables and given/known data 2. There are four masses hanging by a rope from the ceiling, as shown in the figure. Two of the tensions and three of the masses have been measured. Show that the fourth mass can be expressed as m4 =[m1T2/(T1 − T2)]− m2 − m3. 2. Relevant equations F=ma, F1=-F2, T=ma 3. The attempt at a solution I think that (m1+m2+m3+m4)g=T1 and (m2+m3+m4)g=T2 I tried solving for g and substituting and try and solve for m4 but I just find it impssible to do.