Question
If p = 30 - q - r and pq + r(q + p) = 296 then find the
value of (p 2 + q 2 + r 2 ) .Solution
We have, p = 30 - q - r
So, p + q + r = 30
And, pq + r(q + p) = 296
Or, pq + qr + pr = 296
Using, (p + q + r) 2 = p 2 + q 2 + r 2 + 2(pq + qr + pr)
So, 30 2 = (p 2 + q 2 + r 2 ) + 2 X 296
Or, p 2 + q 2 + r 2 = 900 - 592
Or, p 2 + q 2 + r 2 = 308
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