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UKMT Intermediate Mathematical Challenge, 2021

Algebra Difficulty 3.0 AMC 10/12 Find the answer United Kingdom

What is the result when we simplify the expression (1+1x)(1−2x+1)(1+2x−1)\left(1 + \frac{1}{x}\right)\left(1 - \frac{2}{x+1}\right)\left(1 + \frac{2}{x-1}\right)?

(A) 11 (B) 1x(x+1)\frac{1}{x(x+1)} (C) 1(x+1)(x−1)\frac{1}{(x+1)(x-1)} (D) 1x(x+1)(x−1)\frac{1}{x(x+1)(x-1)} (E) x+1x\frac{x+1}{x}

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