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Question
If a + b = 10 and ab = 18, find the value of a2 + b2
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Solution
We have (a + b)2 = a2 + 2ab + b2
(a + b)2 = a2 + b2 + 2ab
given a + b = 0 and ab = 18
102 = a2 + b2 + 2(18)
100 = a2 + b2 + 36
100 – 36 = a2 + b2
a2 + b2 = 64
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