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Question
Expand the following, using suitable identities.
(x + 3)(x + 7)
Sum
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Solution
We have,
(x + 3)(x + 7) = x2 + (3 + 7)x + 3 × 7 ...[Using the identity, (x + a)(x + b) = x2 + (a + b)x + ab]
= x2 + 10x + 21
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Chapter 7: Algebraic Expression, Identities and Factorisation - Exercise [Page 232]
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