Engineering Solving for Req in a Series Circuit - Understanding Resistors and Voltage

[J.live]

Homework Statement

Solve for Req

The Attempt at a Solution

The resistors in the middle can be added to total of 5 ohms. So then then 5v +5ohms = 10 ohms

Then they are all in series 1.5+10+ 1.5= 12.5? What I don't understand is what do i do with
Rx? or 12.5 is Req?

Here is the circuit:

 

[xcvxcvvc]

hmm. just an fyi: i don't see any circuit beneath your promise for the circuit

 

[J.live]

Sorry about that.

 

[xcvxcvvc]

you are correct that the middle branch can be replaced with 5 ohms. However, it does not add in series with the other 5 ohm resistor to its right. instead, they add in parallel. Then that parallel combination adds in series with the 1.5 and 1 ohm resistors.