physics question help?

Question

What is the change in internal energy of a system which does 7.46 x 10^3 J of work as 8.91 x 10^4 J of heat transfer occurs into the system, and 4.73 x 10^4 J of heat transfer occurs out of the system to the environment?

Answer 1

delta-U = Q - W

= (8.91 - 4.73) x 10^4 J - (7.46 x 10^3) J

= 4.18 x 10^4 J - 7.46 x 10^3 J

= 3.43 x 10^4 J.