Answer
-336 J
Work Step by Step
Internal energy $\Delta U=q+w$ where $q$ the heat transferred and $w$ is the work done.
Work received by the system is positive and work performed by the system is negative.
Therefore, total work $w=96\,J-257\,J=-161\,J$
Heat absorbed is positive and heat released is negative.
As heat is released,
Heat transfer $q=-175\,J$
So, $\Delta U=(-161\,J)+(-175\,J)=-336\,J$
