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  • Question
  • If x + 1/x = 2, then what is value of x - 1/x ?


  • Options
  • A. 0
  • B. 1
  • C. 2
  • D. -2

  • Correct Answer


  • Explanation

    Given that, x + 1/x = 2 ...................(i)
    On squaring both sides, we get
    (x + 1/x)2 = 4
    ? x2 + 1/x2 + 2 = 4
    ? x2 + 1/x2 = 2 ..................................(ii)
    Now, we have
    (x - 1/x)2 = (x2 + 1/x2) - 2x X 1/x
    now put the value of x2 + 1/x2
    (x - 1/x)2 = 2 - 2 = 0 [from Eq. (ii)]
    ? x - 1/x = 0


  • Simplification problems


    Search Results


    • 1. 
      If x + 1/x = 3, then x5 + 1/x5 is equal to?

    • Options
    • A. 123
    • B. 83
    • C. 92
    • D. 112
    • Discuss
    • 2. 
      3x + 2y = 12 and xy = 6, them the value of 9x2 + 4y2 is?

    • Options
    • A. 76
    • B. 80
    • C. 72
    • D. 74
    • Discuss
    • 3. 
      (4 x 4 x 4 x 4 x 4 x 4) 5 x (4 x 4 x 4 ) 8 ÷ (4) 3 = (64) ?

    • Options
    • A. 17
    • B. 10
    • C. 16
    • D. 11
    • Discuss
    • 4. 
      If a * b = a + b + a / b, Then the value of 12 * 4 is

    • Options
    • A. 48
    • B. 19
    • C. 20
    • D. 21
    • Discuss
    • 5. 
      If a 2 + b 2 = a, then the value of a 12 + a 6 + 1 is?

    • Options
    • A. 2
    • B. 3
    • C. -3
    • D. 1
    • Discuss
    • 6. 
      If x + 1/x = 6, then x 4 + 1/x 4 is?

    • Options
    • A. 1152
    • B. 1154
    • C. 1148
    • D. 1150
    • Discuss
    • 7. 
      If x + y = 18 and xy = 72, what is the value of x2 + y2?

    • Options
    • A. 120
    • B. 90
    • C. 180
    • D. Cannot be determined
    • Discuss
    • 8. 
      If x + y = 1, then the value of (x3 + y3 + 3xy) is?

    • Options
    • A. -2
    • B. 1
    • C. 2
    • D. 3
    • Discuss
    • 9. 
      If p + q = 10 and pq = 5, then the numerical value if p/q + q/p will be?

    • Options
    • A. 22
    • B. 18
    • C. 16
    • D. 20
    • Discuss
    • 10. 
      [ (m - n) 3 + (n - r) 3 + (r - m) 3 ] / 6[(m - n) (n - r) (r - m)] =?

    • Options
    • A. 1/2
    • B. 1/3
    • C. 1/5
    • D. 1/6
    • Discuss


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