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## Homework Statement

http://imageshack.us/a/img822/5921/homeworkprobsg22.jpg [Broken]

Determine the values of the node voltages Va and Vb

## Homework Equations

Nodal analysis, V = IR

maybe KVL and/or KCL

## The Attempt at a Solution

I got the wrong answer / not sure what the reference node is used for (I know it's the one connecting to ground though, does it have to do with the current?)

Vb - Va = 12V

Vb = Va + 12V

KCL at a:

1.5A + I = Va/6Ω

I = -1.5A + Va/6Ω

KCL at B: 3.5A + I + Vb/3Ω = 0

Plugging Vb in to KCL at b:

3.5A + I + (Va + 12)/3Ω = 0

Now plugging in KCL at a, and then solving for Va:

3.5A -1.5A + Va/6Ω + (Va + 12V)/3Ω = 0

2A + (Va + 2Va + 24V)/6Ω = 0

2A + (3Va + 24V)/6Ω = 0

(3Va + 24V)/6Ω = -2A

3Va + 24V = -12V

3Va = -30V

thus

Va = -10V which is supposedly wrong and would make Vb = 2V also wrong

Where did I go wrong?

Thank you.

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