Find $V_o$ in the circuit shown given that $V_1 = 4 V$, $V_2 = 9 V$, $V_3 = 3 V$, $V_4 = 12 V$, $R_1 = 39 k\Omega$, $R_2 = 126 k\Omega$, $R_3 = 16 k\Omega$, $R_4 = 32 k\Omega$, $R_5 = 22 k\Omega$, and $R_6 = 28 k\Omega$.

The voltage at the inverting terminal of the op amp, $V_x$, = $V$
The current $I_2$ = $mA$
$V_o =$ $V$
The load current, $I_L$ = $mA$
The output current, $I_o$ = $mA$