$(45$ points$)$ For the circuit in the figure, obtain the Thevenin equivalent circuit across the terminals of $R_L$ and answer:

a$.(15$ points$)$ Fill the values

$\backslash$table$[[$Variable$,$Value,Units,Points$],[$Vth$,,V,7\mathrm{.}5],[$Rth$,,,7\mathrm{.}5]]$

b$.(15$ points$)$ Use the Thevenin equivalent circuit to find the current $i_L$ for the following values of $R_L($if this question is solved not using Thevenin, it will be graded over $70\%).$

$\backslash$table$[[R_L(),$Variable,Value,Units,Points$],[0,i_L,,$A$,5],[5,i_l,,$A$,5],[,i_L,,$A$,5]]$

c$.(15$ points$)$ Briefly, explain why is easier to use the Thevenin equivalent circuit to answer question b $.$