To calculate the change in internal energy U of a system, we can use the first law of thermodynamics, which states:U = q + wwhere U is the change in internal energy, q is the heat exchanged with the surroundings, and w is the work done on or by the system.In this case, the system releases 350 J of heat to the surroundings, so q = -350 J negative because heat is released . The system also does 200 J of work on its surroundings, so w = -200 J negative because work is done on the surroundings .Now, we can plug these values into the equation:U = -350 J + -200 J U = -550 JThe change in internal energy of the system is -550 J.