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Discussion :: Surds and Indices

  1.  

    If x = 3 +2 2, then the value of X - 1 is:
    X
  2. A.

    1

    B.

    2

    C.

    22

    D.

    33

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    Answer : Option B

    Explanation :

    [x1X)2=X+1X2

    =(3+22)+ \frac { 1 } {(3+2€‹€‹€‹€‹€‹€‹ \sqrt{2)}} -2

     =(3+2\sqrt{2})+ \frac { 1 } {(3+2€‹€‹€‹€‹€‹€‹ \sqrt{2)}} *\frac {( 3-€‹€‹€‹€‹2 \sqrt{2})} { (3-2\sqrt{2} )} -2

    =(3+2\sqrt{2})+(3-2\sqrt{2})-2

    =4

    [\sqrt{X}-\frac { 1 } { \sqrt{X} }]=2


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