Answer
$\Delta E_{int}=-45J$
Work Step by Step
We know that;
$W=P\Delta V$
We plug in the known values to obtain:
$W=(25)(1.8-3.0)=-30J$
We also know that:
$\Delta E_{int}=Q-W$
We plug in the known values to obtain:
$\Delta E_{int}=-75-(-30)=-45J$
