Answer 1

As shown in the circuit diagram all the 3Ω resistors re connected in parallel.

`1/R_1=1/3+1/3+1/3`

`R_1=1Omega`

Resistors 4Ω and 6Ω are connected in parallel.

`1/R_2=1/4+1/6=5/12`

`R_2=12/5Omega`

Now R₁, R₂ and 5Ω are connected in series

`R_(AB)=1+12/5+5`

`R_(AB)=42/5`

`R_(AB)=8.4Omega`