Answer
70 J
Work Step by Step
There are two steps:
$\Delta$$E_{total}$ = $\Delta$$E_{1}$ + $\Delta$$E_{2}$
Each internal energy step is composed of heat and work
$\Delta$E = q + w
Step 1:
$\Delta$$E_{1}$ = 72 J + 35 J = 107 J
Step 2:
$\Delta$$E_{2}$ = 35 J - 72 J = -37 J
Step 3: Plug those values into equation one
$\Delta$$E_{total}$ = 107 J - 37 J = 70 J
