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प्रश्न
If a + b = 5 and a2 + b2 = 13, then ab = ?
विकल्प
12
6
5
13
MCQ
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उत्तर
6
Explanation;
Hint: (a + b)2 = 25
13 + 2ab = 25
2ab = 12
ab = 6
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