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Question
Using suitable identities, evaluate the following.
(69.3)2 – (30.7)2
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Solution
We have,
(69.3)2 – (30.7)2 = (69.3 + 30.7)(69.3 – 30.7) ...[Using the identity, (a + b)(a – b) = a2 – b2]
= 100 × 38.6
= 3860
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