Solving a circuit with a dependent current source?

What is current ib? (aka current accross 2 ohm resistor).



The diamond shaped thing is a dependent current source that is dependent on ia (current across the 8 ohm resistor) and has a gain of 2 ( in other words it is 2ia).

 

Set up some nodal equasions

Ib=Ia+2Ia Current at top Node
R3*Ia= 42v - Ib*2 Voltage at top node
R2*2Ia=42v - Ib*2

these simplify down to this

Ib=3Ia
8*Ia=42-(Ib*2)
8*Ia=42-(Ib*2) <--- we can toss this one.

Ib=3Ia
8*Ia=42-(Ib*2)

Now we have a current equasion and a voltage equasion.
2 equasions, 2 unknowns, there you go. Basic algebra now.