Problem + Hard 54-1    Source:  Problem 11.16 - page 232 -    EDMINISTER, Joseph A. -   Book: Electric Circuits - 2nd Edition - Ed. McGraw Hill - 1971.

Three impedances, Z₁ = 10 ∠+30°, Z₂ = 20 ∠0° and Z₃ = 5 - j5, must be connected successively to terminals A-B of the circuit shown in the figure below. Determine the power dissipated in each of them.

Problem + Hard 54-2    Source:  Problem 6.7 - page 95 -   EDMINISTER, Joseph A. -   Book: Electric Circuits - 2nd Edition - Ed. McGraw Hill - 1971.

The effective values ​​of the currents I₁, I₂ and I_T are respectively 18 , 15 and 30 A. Determine the unknown impedances R and X_L.