InterviewSolution
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InterviewSolution
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निम्न को सरल कीजिए।(i) (4x + 2y)3 + (4x – 2y)3(ii) (4x + 2y)3 – (4x – 2y)3(iii) (a + 3)3 + (a – 3)3 |
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Answer» (i) (4x + 2y)3 = (4x)3 + (2y)3 + 3. (4x) . (2y) (4x + 2y) = 64x3 + 8y3 + 24xy (4x + 2y) = 64x3 + 8y3 + 96x2y + 48xy2 (4x – 2y)3 = (4x)3 + (-2y)3 + 3. (4x) (-2y) (4x -2y) = 64x3 – 8y3 – 24xy (4x -2y) = 64x3 – 8y3 – 96x2y + 48xy2 इसलिए (4x + 2y)3 + (4x – 2y)3 = 128x3 +96xy2 (ii) (4x + 2y)3 – (4x – 2y)3 = 64x3 + 8y3 + 96x2y + 98xy2 – (64x3 – 8y3 – 96x2y + 48xy2) = 64x3 + 8y3 + 96x32y + 48xy2 – 64x3 + 8y3 + 96x2y – 48xy2 = 16y3 + 192x2y (iii) (a + 3)3 = a3 + 27 + 3a . 3(a + 3) = a3 + 27 + 9a2 + 27a (a – 3)3 = a3 – 27 – 3a – 3(a – 3) = a3 – 27 – 9a2 + 27a ∴ (a + 3)3 + (a – 3)3 = 2a3 +54a |
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