Find V1 & V2 with Nodal Voltage Analysis

[AxeWhyZ]

Homework Statement

Find V1 and V2 by Nodal Analysis

Homework Equations

The Attempt at a Solution

In order to find V1 and V2, I will have to define voltages at node 1 and node 2 as Vx and Vy, so that when I apply KCL at node 1, I will get:

(Vx-240)/3 + (Vx-Vy)/6 + 10=0

While there is a 30 Ohm resistor at node 2 where I can label the voltage Vy, where should I label the voltage Vx when there is no element? Is this the right way to label the voltage Vx:

And if it is the right way, what is the logic?

 

[mfb]

I would draw an arrow and label that, but yes, this is the right approach if you want to reference your Vx to the lower node (a good choice).