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  1. If x4 +
    1
    = 119, and x > 1, then find the positive value of x3 -
    1
    .
    x4x3

    1. 25
    2. 27
    3. 36
    4. 49
Correct Option: C

x4 +
1
= 119
x4

x2 +
1
2 - 2 = 119
x2

x2 +
1
2 = 119 + 2 = 121
x2

x2 +
1
2 = (11)2
x2

⇒ x2 +
1
= 11
x2

x -
1
2 + 2 = 11
x

x -
1
2 = 11 - 2 = 9 = 32
x

⇒ x -
1
= 3
x

On cubing both sides,
x -
1
3 = 27
x

⇒ x3 -
1
- 3x.
1
x -
1
= 27
x3xx

⇒ x3 -
1
- 3 × 3 = 27
x3

⇒ x3 -
1
= 27 + 9 = 36
x3



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