Same chapter3 marksDifficulty: Medium
Evaluate (997)2 using a standard identity.
Expansions
3 marksDifficulty: Medium
If a + b = 7 and ab = 12, find a2 + b2 and a3 + b3.
Original Khojo Papers practice question — not from a past board paper.
Answer
a2 + b2 = 25 and a3 + b3 = 91
No citable source has been recorded for this record. Treat it as practice material, not as fact.
Explanation
a2 + b2 = (a + b)2 − 2ab = 49 − 24 = 25, and a3 + b3 = (a + b)3 − 3ab(a + b) = 343 − 252 = 91.
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Expand (a + b + c)2 and use it to evaluate (10 + 2 + 3)2 without direct multiplication.
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If x + 1/x = 5, find x2 + 1/x2.
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Same chapter1 markDifficulty: Medium
If x + 1/x = 3, then x2 + 1/x2 is:
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