During a thermodynamic process, a system goes from state A to state B. They supply 800 J of heat and the system does 200

[answerhappygod]

During a thermodynamic process, a system goes from state A to
state B.
They supply 800 J of heat and the system does 200 J of work.
(a) For this transition, what is the change in the internal energy
of the system?
(b) If the system then moves from state B to state A, what is its
change in
internal energy?
(c) If work is done in moving from A to B along a different path,
W'AB =
900 J over the system, how much heat is exchanged? Was heat
absorbed or released?
Justify your answer.