Find the power absorbed or delivered by each of the elements in following circuits.

Описание: In order to complete these 4 problems we need to know and use the following:
The passive sign convention is satisfied when the current enters through the
positive terminal of an element and p = +vi. If the current enters through
the negative terminal, p = −vi.
In fact, the law of conservation of energy must be obeyed in any
electric circuit. For this reason, the algebraic sum of power in a circuit,
at any instant of time, must be zero.
Kirchhoff's Current Law or KCL, states that the algebraic sum
of ALL the currents entering and leaving a node must be equal
to zero, I(exiting) + I(entering) = 0. This idea by Kirchhoff is
commonly known as the Conservation of Charge.

Problems
1) A circuit with four elements, p1 = 60 W absorbed, p3 = −145 W absorbed,
and p4 = 75 W absorbed. How many watts does element 2 absorb?
2) Find the power delivered or absorbed by each of the elements in following circuits.
3) Find the current (I) and the power (P) absorbed by each element in
the following network (circuit).
4) Find the voltage Vo and the power absorbed by each element in the circuit.