1. The problem statement, all variables and given/known data A mass,M, is fixed at a position of 3m. Another mass, 2M, is fixed at the position -1m. What position(s) can a third mass, 3M, be placed so that it is in equilibrium. 2. Relevant equations The only thing I could think of is M(3)+2M(-1)+3Mx=0 3. The attempt at a solution I tried the center of mass equation and got the same wrong answer.