Physics 2: RC Circuits

What is the total energy stored by the 36 $\mu$F capacitor?

If the potential difference across the 20 $\mu$F capacitor is 12 V. What is the potential difference supplied by the battery? How much energy is stored in the 25 $\mu$F capacitor?

Find the current flowing through the other two branches and the value of the resistor in the circuit below.

How much current flows through the 3 $\Omega$ resistor? The 4.5 $\Omega$ resistor? What is the value of $\Sigma$?