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    Question

    If (a – 2b) = 8 and 2ab = 9, then find the value of (a

    + 2b).
    A 12 Correct Answer Incorrect Answer
    B 6 Correct Answer Incorrect Answer
    C 10 Correct Answer Incorrect Answer
    D 8 Correct Answer Incorrect Answer

    Solution

    (a – 2b) = 8         Both sides Squaring. (a – 2b)2 = 82 a2+4b2-4ab =64. a2+4b2 =64+4ab …. (2) (a + 2b)2 =a2+4b2+4ab (a + 2b)2 =64 +8ab =64+8×9/2 (a + 2b)2 =100 (a+2b) =10

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