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A − b = 3, a2 + b2 = 29. ∴ ab = ______. - Mathematics

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Question

a − b = 3, a2 + b2 = 29. ∴ ab = ______.

Options

  • 19

  • 10

  • 18

  • 12

MCQ
Fill in the Blanks
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Solution

a − b = 3, a2 + b2 = 29. ∴ ab = 10.

Explanation:

a2 + b2 = (a − b)2 + 2ab

29 = 9 + 2ab

29 − 9 = 2ab

∴ 2ab = 20

∴ ab = `20/2`

∴ ab = 10

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Chapter 3: Expansions - MULTIPLE CHOICE QUESTIONS [Page 39]

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B Nirmala Shastry Mathematics [English] Class 9 ICSE
Chapter 3 Expansions
MULTIPLE CHOICE QUESTIONS | Q 14. | Page 39
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