Determine the resistance R_0, equivalent resistance of the circuit, (a combination of resistances R₁ = 6 Ω and R₂ = 3 Ω, which are connected in parallel in the circuit as shown below) and the total current I flowing in the circuit, and currents I₁ and I₂ flowing through resistances R₁ and R₂. It is also known that the power of the circuit is U = 12V.