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  1. If x > 1 and x +
    1
    = 2
    1
    , then the value of x4 +
    25
    is
    x12x4

    1. 58975
      20736

    2. 59825
      20736

    3. 57985
      20736

    4. 57895
      20736
Correct Option: A

x +
1
= 2
1
=
25
x1212

On squaring both sides,
x +
1
2 =
25
2
x12

⇒ x2 +
1
+ 2 =
625
x2144

⇒ x2 +
1
=
625
- 2
x2144

⇒ x2 +
1
=
625 - 228
=
337
x2144144

x -
1
2 + 2 =
337
x144

x -
1
2 =
337
- 2
x144

=
337 - 288
=
49
144144

⇒ x -
1
= √
49
=
7
x14412


Required answer =
337
×
25
×
7
=
58975
144121220736



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