Hello Eiba!
Looks like you have not posted the complete question. This question appears to have a diagram too that gives details about what are x, y and z. Also, the values of x, y, and z cannot be determined without knowing other clues. It is not clear which angle you are talking about in the question. So kindly post the complete question along with the diagram if there is any.
Question : What is the simplified value of $\frac{(x+y+z)(x y+y z+z x)–x y z}{(x+y)(y+z)(z+x)}$?
Option 1: $y$
Option 2: $z$
Option 3: $1$
Option 4: $x$
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