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  1. When 2x +
    2
    = 3 , then value of x3 +
    1
    + 2 is
    xx3

    1. 2
      7

    2. 7
      8

    3. 7
      2

    4. 8
      7
Correct Option: B

2x +
2
= 3
x

On dividing by 2,
x +
1
=
3
x2

On cubing both sides,
x +
1
3 =
27
x8

⇒ x3 +
1
+ 3x +
1
=
27
x3x8

⇒ x3 +
1
+
3 × 3
=
27
x328

⇒ x3 +
1
=
27
-
9
x382

⇒ x3 +
1
=
27 - 36
x38

⇒ x3 +
1
=
-9
x38

∴ x3 +
1
+ 2 = 2 -
9
=
16 - 9
=
7
x3888



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