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Q.1. If p(x) = x2 – 2√2 x + 1, then find p (2√2) .
Sol. Since, p(x) = x2 – 2 √2 x + 1
= 4 (2) – 4 (2) + 1 = 8 – 8 + 1 = 1
Q.2. If a + b + c = 9, and ab + bc + ca = 26, find a2 + b2 + c2
Sol. (a + b + c)2 = (a2 + b2 + c2) + 2 (ab + bc + ca)
⇒ (9)2 = (a2 + b2 + c2) + 2 (26) = (a2 + b2 + c2) + 52
⇒ a2 + b2 + c2 =92– 52 = 81– 52 = 29
Q.3. Factorise :
Sol.
Q.4. If a, b, c are all non-zero and a + b + c = 0, prove that
Sol. ∵ a + b + c = 0 ⇒ a3 + b3 + c3 – 3abc = 0
or a3 + b3 + c3 = 3abc ⇒
Q.5. Prove that (a + b + c)3 – a3 – b3 – c3 = 3(a + b) (b + c) (c + a)
Sol.
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