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Question
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(7x + 8y)3
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Solution
(7x + 8y)3
= `(7x)^3 + 3 xx (7x)^2 xx (8y) + 3 xx (7x) xx (8y)^2 + (8y)^3` …[∵ (a + b)3 = a3 + 3a2b + 3ab2 + b3]
= `343x^3 + 3(49x^2)(8y) + 3(7x)(64y^2) + 512y^3`
= `343x^3 + 1176x^2y + 1344xy^2 + 512y^3`
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