$2-23$ Determine the voltage Vo in Problem $2-9($Figure P$2-9)$ using the principle of superposition.

$2-9$ The voltage $V_0$ is to be determined in the circuit of Figure P$2-9.$ Show that by performing a source transformation to the left of $x-y,$ the circuit reduces to a single node$-$pair form as far as the part of the circuit of interest is concerned. Using the modified circuit, determine $V_0.$