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If $$x = 3 + 2\sqrt 2 ,$$    then the value of $$\left( {\sqrt x - \frac{1}{{\sqrt x }}} \right)$$   is:

A. 1

B. 2

C. $$2\sqrt 2 $$

D. $$3\sqrt 3 $$

Answer: Option B

Solution(By Examveda Team)

$$\eqalign{ & {\left( {\sqrt x - \frac{1}{{\sqrt x }}} \right)^2} \cr & = x + \frac{1}{x} - 2 \cr & = \left( {3 + 2\sqrt 2 } \right) + \frac{1}{{\left( {3 + 2\sqrt 2 } \right)}} - 2 \cr & = \left( {3 + 2\sqrt 2 } \right) + \frac{1}{{\left( {3 + 2\sqrt 2 } \right)}} \times \frac{{\left( {3 - 2\sqrt 2 } \right)}}{{\left( {3 - 2\sqrt 2 } \right)}} - 2 \cr & = \left( {3 + 2\sqrt 2 } \right) + \left( {3 - 2\sqrt 2 } \right) - 2 \cr & = 4 \cr & \therefore \left( {\sqrt x - \frac{1}{{\sqrt x }}} \right) = 2 \cr} $$

This Question Belongs to Arithmetic Ability >> Surds And Indices

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Comments ( 1 )

  1. Fakhrul Miazi
    Fakhrul Miazi :
    3 years ago

    I don't get the fourth line.

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