Nevermind... I confirmed this actually does work. For some reason I was setting Io equal to (V1-20)/4 instead of (20-V1)/4. I seemed to have not taken into account the current direction.
Just to clarify the title... Basically for the below circuit we are required to find Vth, Rth and Vo. However, the method of solving this problem is a little strange to me, because as you can see, the source has a phase angle of 30 degrees. The solution to this problem basically says (to find...