4/(√x - √(x - 2)) × (√x + √(x - 2))/(√x + √(x - 2))
= 4 (√x + √(x - 2)) / ((√x)² - (√(x - 2))²)
= 4 (√x + √(x - 2)) / (x - (x - 2))
= 4 (√x + √(x - 2)) / (x - x + 2)
= 4 (√x + √(x - 2)) / 2
= 2 (√x + √(x - 2))
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