Let me give another approach, maybe simplistic.
There are several theorems or methods, but let's not forget that all those theorems come from the observation, someone found a pattern and proved its correctness.
However, when you are in front of a circuit like this, that is quite simple. Before applying theorems I think it is better to think by yourself.
Then, the first thing I see in this circuit is a parallel of two resistors that looks are there to confuse or to raise doubts, but I need to not be afraid and replace that parallel as follows.

simulate this circuit – Schematic created using CircuitLab
Then you get the following circuit where you want to find V1 and if you observe it you can see that there are three currents involved in it, Ie flowing through the equivalent parallel resistor, I2 flowing through R2 and I1 flowing through R1. You also know from Kirchoff's law (and this a law, not a theorem) that I1 = Ie + I2.

simulate this circuit
Each current's value is the following:
$$I_e=\frac{V_a-V_1}{R_e}$$
$$I_2=\frac{V_b-V_1}{R_2}$$
$$I_1=\frac{V_1}{R_1}$$
With a bit of algebra you reach your V1 = 12.3077 volt