$4\mathrm{.}3$ a$)$ Use the node$-$voltage method to find the power associated with each source in the circuit shown.

b$)$ State whether the source is delivering power to the circuit or extracting power from the circuit.

Answer:

$($a$)p_{50V}=-150W,p_{3i_1}=-144W,p_{5A}=-80W$

$($b$)$ all sources are delivering power to the circuit.