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Question
Evaluate the following using suitable identity:
(99)3
Solution
It is known that,
(a + b)3 = a3 + b3 + 3ab(a + b) and (a − b)3 = a3 − b3 − 3ab(a − b)
∴ (99)3 = (100 − 1)3
= (100)3 − (1)3 − 3(100)(1)(100 − 1)
= 1000000 − 1 − 300(99)
= 1000000 − 1 − 29700
= 970299
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