Mathematics
If (a + b + c) = 15 and (ab + bc + ca) = 74, find the value of (a2 + b2 + c2).
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Answer
Given,
(a + b + c) = 15
(ab + bc + ca) = 74
Using identity,
⇒ (a + b + c)2 = (a2 + b2 + c2) + 2 (ab + bc + ca)
⇒ (15)2 = (a2 + b2 + c2) + 2 (74)
⇒ 225 = (a2 + b2 + c2) + 148
⇒ 225 - 148 = (a2 + b2 + c2)
⇒ (a2 + b2 + c2) = 77
Hence, (a2 + b2 + c2) = 77.
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