the correct answer is 9A. I did it using mesh analysis (loops). You get the equation:
42 - 2*ib - 8*ib + 8*(2*ia) = 0
for the first loop (simply summing the voltages around the loop)
8*ib - 8*(2*ia) - 4*(2*ia) = 0
for the second loop.
From here you have two equations and two unknowns, should be easy to solve. I don't know if you've done mesh analysis yet, but I highly recommend becoming friends with it. You'll use it a LOT.
edit: I changed the picture a little to help visualize what I did.
note: The dependent current supply didn't do anything, but if it's gain were different, this method would still give you the correct answer.