My work and the problem are attached, I have attempted to calculate both the thevenin resistance and norton equivalent current, but I believe my method is wrong, as I haven't gotten the correct answers. Any help or guidance is appreciated, thanks in advance.

 

Your equation implies that, with the sources turned off, R1 and R2 are in series but R3 and R4 are in parallel.

Redraw the circuit with both sources set to zero and post that (it is a critical part of your work).