I have a problem with this series/parallel circuit. How do I find the equivalent series resistance? I assumed R1 + R2|R3 + R4|R5, is this correct?

 

I'd calculate the parallel resistance of the 2ohm and 4ohm.
Put that in series with the 6ohm.
Put the result in parallel with the 5ohm
Put that result in series with the 9ohm.
If your answer is nearly but not quite 12ohms that should be right.

 

Rz is equal
Rz = R1 + R2||(R3+R4||R5) = 443/37

 

so is their only one answer to this then?

 

so is their only one answer to this then?

Yep - about 11.97 ohms as Jony130 demonstrated.

 

Hello,

I have redrawn the schematic a little bit to show you wich resistors are parallel to wich.

Bertus