What is the value of: 1 / (1 + x^(b-a) + x^(c-a)) + 1 / (1 + x^(n-b) + x^(c-b)) + 1 / (1 + x^(a-c) + x^(b-c)) - CDS Elementary Mathematics 2018 (I)

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What is the value of: 1 / (1 + x^(b-a) + x^(c-a)) + 1 / (1 + x^(n-b) + x^(c-b)) + 1 / (1 + x^(a-c) + x^(b-c)) where x ≠ 0?