Let f(x)=x−1x+1f(x) = \frac{x-1}{x+1}f(x)=x+1x−1. Find the set of all xxx such that f(f(f(x)))=xf(f(f(x))) = xf(f(f(x)))=x.
x∈R∖{−1,0,1}x \in \mathbb{R} \setminus \{-1, 0, 1\}x∈R∖{−1,0,1}
x∈R∖{−1,0}x \in \mathbb{R} \setminus \{-1, 0\}x∈R∖{−1,0}
x=0x = 0x=0
No such xxx exists