EduGoog

If (x2 + 1/x2) = 102, then (x - 1/x) is :

Option:
A. 8
B. 10
C. 12
D. 13
Answer: B . 10

Justification:

(x2 + 1/x2) = 102

→ (x2 + 1/x2 - 2) = 100

→ (x - 1/x)2 = 102

→ (x - 1/x) = 10.

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