giải giúp em bài 1.6 với ạ

Mạch: `R_5////{R_1  nt  [R_3////(R_2  nt  R_4)]}`

`R_[24]=R_2+R_4=1+3=4Omega`

`R_[234]=[R_3R_[24]]/[R_3+R_[24]]=[6*4]/[6+4]=2.4Omega`

`R_[1234]=R_1+R_[234]=3.6+2.4=6Omega`

`R=[R_5R_[1234]]/[R_5+R_[1234]]=[6R_5]/[6+R_5]`

`U=IR=1.5*[6R_5]/[6+R_5]=[9R_5]/[6+R_5]`

`U_5=U_[1234]=U=[9R_5]/[6+R_5]`

`I_[1234]=[U_[1234]]/[R_[1234]]=[[9R_5]/[6+R_5]]/6=[1.5R_5]/[6+R_5]`

`I_1=I_[234]=I_[234]=[1.5R_5]/[6+R_5]`

`U_[234]=I_[234]R_[234]=[1.5R_5]/[6+R_5]*2.4=[3.6R_5]/[6+R_5]`

`U_3=U_[24]=U_[234]=[3.6R_5]/[6+R_5]`

Mà `U_3=2.4V`

`-> 2.4=[3.6R_5]/[6+R_5]`

`-> R_5=12Omega`