Which technique do I use to solve this problem?
Hi,
I just directly realised that there is no "COM" on the circuit, Volts are mesured in relation to another point or reference. So i chosed my own reference, the lower voltage level so i have only positive VOLTS, the redraw the circuit and VOILA i have a simple Passif audio summing circuit, i think with millman analysis or node analysis you can get the voltage easily.
Sometimes is just a matter of perspective to see a solution to a problem.