$(20$ points$)$

Annlv source transformation to find $v_x$ in the given circuit where $V=45V.$

$4.(20$ points$)$

F

$5.(20$ points$)$

Obtain the Thevenin equivalent seen at terminals of the circuit given below, where $R_1=4\mathrm{.}0$ and $R_2=1\mathrm{.}0.$