Correct Answer: x + y
Explanation:
xy = [(√2 + 1)/(√2 - 1)] x [(√2 - 1)/(√2 + 1)] = 1 ∴ 3(xy + 1) = 3(1 + 1) = 6 Now, x + y = [(√2 + 1)/(√2 - 1)] + [(√2 - 1)/(√2 + 1)] = (√2 + 1)2 + (√2 - 1)2 / (√2 - 1) (√2 + 1) = (2 + 1 +2√2) + (2 + 1 - 2√2) / (2 - 1) = 6 ∴ 3(xy + 1) = x + y