[gabriel.colon32]

Greetings, can someone explain why my answer is wrong in this problem?

What is the internal energy change of a system if for a process the system absorbs 71kJ of thermal energy and does 12kJ of work?

I just substracted 12 to 71 to get the net value of kJ gained, but the answer is 383kJ. Did I forgot to use an equation or something?

Thanks in advance