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  1. If x = √3 + √2 , then the value of x3 +
    1
      is
    x3


    1. 6√3
    2. 12√3
    3. 18√3
    4. 24√3
Correct Option: C

Using Rule 8,
x = √3 + √2

1
=
1
x3 + √2

1
=
1
×
3 - √2
x3 + √2 3 - √2

1
=
3 - √2
= √3 - √2
x3 - 2

∴ x +
1
= √3 + √2 + √3 - √2
x

⇒ x +
1
= 2√3
x

x3 +
1
= x +
1
3 - 3x .
1
x +
1
x3xxx

= ( 2√3 )3 - 3( 2√3 )
= 24√3 - 6√3 = 18√3



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