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Let f(x) = 1 x 1 x + − , x ∈ R – {0, – 1, 1}. If f n+1 (x) = f(f n (x)) for all n ∈ N, then f 6 (6) = f 7 (7) is equal to

1. 6 7
2. 2 3 −
3. 12 7
4. 12 11 −

Correct answer: 2 3 −

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