1. The problem statement, all variables and given/known data http://imageshack.us/a/img713/9389/homeworkprobsg23.jpg [Broken] Determine node voltages for the circuit 2. Relevant equations V = IR, KCL Supernode equations 3. The attempt at a solution I am sorry to say that There is a LOT of stuff in this problem I still need help with, like how/ when to apply supernodes. Is it true that where you see a ground node, then they do NOT want you to put supernode there? Or can you really put it anywhere with a voltage / current source? The only equation for this problem I know for sure to make out at this point is Va - Vc = 10V Putting the supernodes like this: http://imageshack.us/a/img94/5332/homeworkprobsg23edit.jpg [Broken] I think I would get (with both currents in the middle going towards B, if I can set it that way): 5A - 2A = (Va - Vb)/10Ω and then 5A - 2A = (Vc - Vb)/40Ω I do not know if this is right at all though. Sorry if I should know this well already too, but can a current from another source (ie from the 5A and 2A) pass freely through a wire with a voltage source (ie 10V and 12V)? Thank you.