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Using the method of successive subtraction examine whether or not the following numbers are perfect cubes:(i) 130(ii) 345 |
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Answer» (i) 130 130 – 1 = 129 129 – 7 = 122 122 – 19 = 103 103 – 37 = 66 66 – 61 = 5 Other number to be subtracted is 91, which is greater than 5 ∴130 is not a perfect cube. (ii) 345 345 – 1 = 344 344 – 7 = 337 337 – 19 = 318 318 – 37 = 281 281 – 61 = 220 220 – 91 = 129 129 – 127 = 2 Other number to be subtracted is 169, which is greater than 2 ∴ 345 is not a perfect cube |
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