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Question
If a2 + b2 = 74 and ab = 35, then find a + b.
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Solution
Given, a2 + b2 = 74 and ab = 35
Since, (a + b)2 = a2 + b2 + 2ab ...[Using the identity, (a + b)2 = a2 + b2 + 2ab]
∴ (a + b)2 = 74 + 2 × 35
⇒ (a + b)2 = 144
⇒ `a + b = sqrt(144)` ...[Taking square root]
⇒ a + b = 12 ...[Rejecting – ve sign]
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