Monday, 26 December 2016

Question of the day 25-12-2016

Question of the day:

If a - b = 3 and a2 + b2 = 99, find the value of ab?



a)45              b)40           c)90          d)None

3 comments:

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    1. Answer: Option d
      Explanation:
      2ab = (a2 + b2) - (a - b)2
      = 29 - 9 = 20
      ab = 10.

      Delete
    2. Answer: Option d
      Explanation:
      2ab = (a2 + b2) - (a - b)2
      = 29 - 9 = 20
      ab = 10.

      Delete