Elotrostatics: Energy of capacitors in series and parallel
There is an attachment of what the problem is. I also wrote a little bit of what I tried.
Consider the group of capacitors shown in Figure 21-39, where C1 = 13 µF and C2 = 6.4 µF. Terminals A and B are connected to a 9.0 V battery. Find the energy stored in each capacitor.
(See diagram in attachment)