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Question
If a2 + b2 = 29 and ab = 10, find : a + b
Sum
Solution
(a + b)2 = a2 + b2 + 2ab
⇒ (a + b)2 = 29 + 2×10
⇒ (a + b)2 = 29 + 20
⇒ (a + b)2 = 49
⇒ a + b = `sqrt49`
⇒ a + b = ±7
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Application of Formulae
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