I am trying to find \$v\_0\$ in this circuit (voltage across \$R4\$):

![schematic](https://i.stack.imgur.com/x3nBw.png)

[simulate this circuit](/plugins/schematics?image=http%3a%2f%2fi.stack.imgur.com%2fx3nBw.png) – Schematic created using [CircuitLab](https://www.circuitlab.com/)

![Schematic](https://i.stack.imgur.com/QjesI.jpg)

The issue I am having is that I would have known that the current going into the 16 ohm resistor would have been the same as the one going in the negative terminal, but that's only if they are both going into the negative terminal. I know that its 0 volts to ground on the right side. And 0 volts in between the + and -. 

Can someone help me find \$v\_0\$?