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Question
Expand the following:
(3a – 2b)3
Solution
(3a – 2b)3 = (3a)3 – (2b)3 – 3(3a)(2b)(3a – 2b) ...[Using identity, (a – b)3 = a3 – b3 – 3ab(a – b)]
= 27a3 – 8b3 – 18ab(3a – 2b)
= 27a3 – 8b3 – 54a2b + 36ab2
= 27a3 – 54a2b + 36ab2 – 8b3
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