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Home ‣ Aptitude ‣ Elementary Algebra See What Others Are Saying!
  • Question

  • Two candidates attempt to solved a quadratic equation of from x 2 + px + q = 0. One starts with a wrong value of p and finds the roots to be 2 and 6. Other starts with a wrong value of q and find the root to be 2 and -9. Find the correct roots and equation?


  • Options
  • A. -3, -2 and x x2 + 9x + 18
  • B. 3, 4 and x2 + 8x + 15
  • C. -3, -4 and x2 + 7x + 12
  • D. 2, 6 and x2+ 7x + 12

  • Correct Answer
  • -3, -4 and x2 + 7x + 12 

    Explanation

    When p is wrong i.e., -b/a = (? + ?) is wrong but c/a =(??) is correct.
    Then ?? = c/a = 2 x 6 = 12 ....(i)

    Again, when q is wrong i.e.,c/a = (?.? ) is wrong but -b/a = ?+? is correct.
    Then, -b/a = ?+?= 2 + (-9) = -7

    So, the required correct quadratic equations is
    x2 -(? + ?)x + ?.?=0
    ? x2 - (-7)x + 12 = 0
    ? x2 + 7x + 12 = 0
    and correct roots this equations are -3, -4.

    • More questions

    • 1. What value should come in place of the question mark(?) in the following question? (?) - 19657 - 33994 = 9999

    • Options
    • A. 63650
    • B. 53760
    • C. 59640
    • D. 61560
    • E. None of these
      • Discuss
    • 2. What value should come in place of the question mark(?) in the following question? (?) + 3699 + 1985 - 2047 = 31111

    • Options
    • A. 34748
    • B. 27474
    • C. 30154
    • D. 27574
    • E. None of these
      • Discuss
    • 3. What value should come in place of the question mark(?) in the following question?
      250 / √ ? = 10

    • Options
    • A. 25
    • B. 250
    • C. 625
    • D. 2500
      • Discuss
    • 4. What value should come in place of the question mark(?) in the following question?
      ? + 6207 - 9038 = 107

    • Options
    • A. 2724
    • B. 2938
    • C. 2814
    • D. None of these
      • Discuss
    • 5. What value should come in place of the question mark(?) in the following question?
      ? - 4799 = 1714

    • Options
    • A. 6513
    • B. 7403
    • C. 3085
    • D. None of these
      • Discuss
    • 6. What value should come in place of the question mark(?) in the following question?
      9501 -? = 3697

    • Options
    • A. 13198
    • B. 5814
    • C. 5804
    • D. 4894
      • Discuss
    • 7. What value should come in place of the question mark(?) in the following question?
      66066 + 6606 + 66 + 6 =?

    • Options
    • A. 258126
    • B. 72744
    • C. 72798
    • D. None of these
      • Discuss
    • 8. What value should come in place of the question mark(?) in the following question?
      ? x 48 = 173 x 240

    • Options
    • A. 545
    • B. 685
    • C. 865
    • D. 495
      • Discuss
    • 9. What value should come in place of the question mark(?) in the following question?
      ? x 11 = 555555

    • Options
    • A. 505
    • B. 5050
    • C. 50505
    • D. 5005
      • Discuss
    • 10. What value should come in place of the question mark(?) in the following question?
      87 x? = 3393

    • Options
    • A. 39
    • B. 49
    • C. 27
    • D. 67
      • Discuss

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