Question

If x² + 1/x² = 102, then x-1/x =
A. 8
B. 10
C. 12
D. 13

Answer 1

Given : x² + 1/x² …….(1)

 

To find :  The value of  x - 1/x .

Solution :

By using an identity : (a – b)² = a² + b² – 2ab

We know that , ( x - 1/x )² =  x² + 1/x² - 2 × x ×1/x

( x - 1/x )² = x² + 1/x² - 2  

( x - 1/x )² = 102 - 2  

[From eq 1]

( x - 1/x )² = 100

Taking square root both sides :  

 x - 1/x = √100

 x - 1/x = 10

Hence the value of  x - 1/x  is 10.

Among the given options option (B) 10 is correct.

HOPE THIS ANSWER WILL HELP YOU…..

 

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Answer 2

Step-by-step explanation:

If x² + 1/x² = 102, then x-1/x =

A. 8

B. 10✅✅

C. 12

D. 13