Network theorem Source Transformation
If you used source transformation to transform the combination of current source and parallel resistor in the left side and the right side into voltage sources, then you can find current, power and voltage only in the components which are external to the sources. 







simulate this circuit &ndash; Schematic created using CircuitLab

Here its only 10 ohms resistor. Calculations on 5 ohm resistor or 4 ohm resistor which are part of the sources, will yield you wrong results.