Node Voltage Analysis: Solving VA & VB

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I am having a hard time trying to determine the voltage at VA and VB. I know that VC = VD = 10V. At first I thought this would be a simple setup, but I'm unsure about how to set up an equation for VA considering that there is a resistor and a voltage source between it and the reference node. I've built this circuit and made measurements with a DMM, I'm just trying to come to the same results using nodal analysis. Can anyone point me in the right direction?
 

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For VA, I have (VA - 6)/100 + (VA - 10)/800 = 0
For VB, I have (VB - 10)/320 + VB/330 = 0
For VC, I have VC = 10
 
You could solve it by using 4 loop currents and then writing the KVL equations for the 4 loops.

Or you could start by simplifying the circuit, for example replace R3 and R5 by a single resistor ...
 
Using mesh current analysis was a breeze, but I am also asked to use node voltage.

As far as your second suggestion, I combined those resistors in the equations above.