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Simplify the following using the formula: (a – b) (a + b) = a2 – b2 :(i) (82)2 – (18)2(ii) (467)2 – (33)2(iii) (79)2 – (69)2 |
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Answer» (i) (82)2 – (18)2 Using formula (a – b) (a + b) = a2 – b2 We get, (82)2 – (18)2 = (82 – 18) (82 + 18) = 64 × 100 = 6400 (ii) (467)2 – (33)2 Using formula (a – b) (a + b) = a2 – b2 We get, (467)2 – (33)2 = (467 – 33) (467 + 33) = (434) (500) = 217000 (iii) (79)2 – (69)2 Using formula (a – b) (a + b) = a2 – b2 We get, (79)2 – (69)2 = (79 + 69) (79 – 69) = (148) (10) = 1480 |
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