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Basic operations, simple factors, factor Theorem, Remainder Theorem, Division of polynomials.

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

Option:
A. 7
B. - 7
C. 9
D. - 9
Answer: C . 9

Justification:

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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