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If (x - 1/x) = 1/2 , then (4x2 + 4/x2) is equal to :

Answer: C. 9

x - 1/x = 1/2
→ (x - 1/x)2= 1/4
→ x2 + 1/x2 - 2 = 1/4
→ x2 + 1/x2 = 9/4
→ (4x2 + 4/x2) = 4 (x2 + 1/x2) = 4 x 9/4 = 9.

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