Le grupez pe toate in serie(1), pe toate in paralel(2) si 6 in serie si 6 in serie, ambele in paralel(3)
Re1= R1+R2+ ... + R12 = 6*12 = 72 Ω
1/Re2 = 1/R1 + 1/R2 + ... + 1/R12 => 1/Re2= 12*1/6 => Re2 = 1/2
[tex]\left \{ {{1/Re3 = 1/Re6' + 1/Re6'} \atop {Re6' = R1+R2+...+R6 = 6*6 =36}} \right.[/tex]
1/Re3 = 1/36+ 1/36 => 1/Re3 = 2/36 = >Re3=36/2 =18 Ω
