I set all sources to 0 so we have Rth=3.667 KΩ
then using superposition and remove the current source and replace it with open circuit so we have Vth1 =-3.333 V
then remove the voltage source and replace it with short circuit so we have Vth2=25 V
so Vth=25-3.3333=21.667 V
other friends tell me that Vth2=30 V
what's the correct ??
