Problem $1(3\mathrm{.}5$ P$)$:

In the circuit shown in the figure, calculate: a$)(1\mathrm{.}5$P$)$ the electric current flowing through each branch; b$)(1$P$)$ the power supplied by the generators and consumed in the resistances; c$)(1$P$)$ the Th$$venin equivalent circuit between $\backslash ($ A $\backslash )$ and $\backslash ($ B $\backslash ).$