Op-amp, Finding the V0
Here's how I would approach the problem.  First, redraw the circuit for clarity, e.g.,







simulate this circuit &ndash; Schematic created using CircuitLab

If there's negative feedback present, the op-amp input terminals have the same voltage (virtual short circuit) and, since there is no current into either input terminal, it follows that

$$I_x = 0$$

Thus,

$$V_x = 5A \cdot R_3 = 5A \cdot 1 \Omega = 5V$$

which means

$$V_+ = V_- = 5V$$

Now, using superposition, write the equation for \$V_o\$ at the inverting input node:

$$5V = V_o \frac{R_4||R_5}{R_6 + R_4||R_5} + (2V + 5\cdot 5V)\frac{R_4||R_6}{R_5 + R_4||R_6}$$

Solving for \$V_0\$ yields

$$V_o = -23V$$