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Using the formula (a - b)2 = (a2 - 2ab + b2), evaluate:(i) (196)2 (ii) (689)2 (iii) (891)2 |
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Answer» (i) We know that, (a – b)2 = (a2 – 2ab + b2) We have (196)2 = (200 - 4)2 = 2002 – 2 (200 × 4) + 42 = 40000 – 1600 + 16 = 3814 (ii) We know that, (a – b)2 = (a2 – 2ab + b2) We have (689)2 = (700 - 11)2 = 7002 – 2 (700 × 11) + 112 = 490000 – 15400 + 121 = 474721 (iii) We know that, (a – b)2 = (a2 – 2ab + b2) We have (891)2 = (900 - 9)2 = 9002 – 2 (900 × 9) + 92 = 810000 – 16200 + 81 = 793881 |
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