How to start solving this circuit
First, you have to pick a reference node to be your ground. I'd suggest the one at the negative end of the two power supplies. There are a few series resistors you can combine, but aside from that, you're probably stuck with mesh equations. You could try making a Thevenin equivalent or doing a delta-wye transform somewhere, but I doubt it's worth the hassle. There's only seven mesh currents, and you can use Ohm's Law to get the top-left one.