This is an expression obtained for resolving a circuit.
I tried for 1 hour now and I’m close but I’m doing something wrong. 

I’m trying to find detA. (details under the photo)

I’m new to this so be kind with me :) 

[![Here it is:](https://i.stack.imgur.com/acoy6.jpg)](https://i.stack.imgur.com/acoy6.jpg)

***detA where A is the first matrice***

$((1/x)+(1/y))\*((1/y)+(1/z))$

I came up with this:
$(1/R1\*R2)+(1/R1\*R3)+(1/R2^2)+(1/R2\*R3)-(-1/R2)^2 =$
$(1/R1)((1/R2)+(1/R3)) + (1/R2\*R3)$

(**note, maybe the parentheses around fractions are useless**)
There are some similarities, it can be random.