Question
If (p + q + r) = 10 and (pq + qr + rp) = 30, then find the
value of (p² + q² + r²).Solution
ATQ,
As we know,
(p + q + r)² = p² + q² + r² + 2(pq + qr + rp)
Or, (10)² = p² + q² + r² + 2 × (30)
So, p² + q² + r² = 100 – 60 = 40
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