The voltage across the circuit is given as 6 V.
So the power dissipated by the 4 ohms resistor is given as P=V2R=624=9W. And,
the power dissipated by the 6 ohms resistor is given as P=V2R=626=6W.
Hence, the power dissipated by the 4 ohms and 6 ohms resistors are 9 W and 6 W.