Hello. I am applying KCL to the circuit in the image below but I am unable to make the equation for the last loop(I dont understand what to do with iz). I will be very thankful if someone could help me out. Thanks

 

Making a Norton's equivalent may be the quickest way. The currents would then add.

 

Making a Norton's equivalent may be the quickest way. The currents would then add.

Can you please tell me how to do it with KCL or KVL ?