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If 3a-2b=7,ab=2.Find the value of 27a3-8b3 |
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Answer» Answer: 3a-2b=7 squaring both SIDES (3a-2b)^2=(7)^2 9a^2-12ab+4b^2 = 49 9a^2-12×2+4b^2 = 49 9a^2-24+4b^2 = 49 9a^2+4b^2 = 49+24 9a^2+4b^2 = 73 a/q..... 27a^3-8b^3 = (3a)^3 - (2b)^3 = (3a-2b) [(3a)^2+6ab+(2b)^2] ........a^3-b^3 = (a-b)(a^2+ab+b^2) = (7) [9a^2+4b^2+6×2] = 7 [73+12] = 7 [ 85] = 595 hope it helps you |
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