Question

${(3 - 5a)}^{2} =$
${49 - 81d}^{2} =$
${27a}^{3} - {x}^{3} =$

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Answer 1

Ответ:

$(3 - 5a) {}^{2} = 9 - 30a + 25a {}^{2} = 25a {}^{2} - 30a + 9$

$49 - 81d {}^{2} = 7 {}^{2} - 9 {}^{2} d {}^{2} = 7 {}^{2} - (9d) {}^{2} = (7 - 9d) \times (7 + 9d)$

$27a {}^{3} - x {}^{3} = 3 {}^{3} a {}^{3} - x {}^{3} = (3 a ){}^{3} - x {}^{3} = (3a - x) \times ((3a) {}^{2} + 3ax + x {}^{2} = (3a - x) \times(9a {}^{2} + 3ax + x {}^{2})$