Алгебра 7 класс.
Алгебра 7 класс.
1) (2x + 5)² = (2x)² + 2(2x)(5) + 5² = 4x² + 20x + 25 2) (6 – 2m)² = (6)² - 2(6)(2m) + (2m)² = 36 - 24m + 4m² = 4m² - 24m + 36 3) (3x + 2y)² = (3x)² + 2(3x)(2y) + (2y)² = 9x² + 12xy + 4y² 4) (2m – 5n)² = (2m)² - 2(2m)(5n) + (5n)² = 4m² - 20mn + 25n² 5) (m – 2n)² = (m)² - 2(m)(2n) + (2n)² = m² - 4mn + 4n² 6) (3x + 5)(3x – 5) = (3x)² - (5)² = 9x² - 25 7) (6 – 7y)(6 + 7y) = (6)² - (7y)² = 36 - 49y² 8) (10 + 8n)(8n – 10) = (10)² - (10)² = 100 - 100 = 0 9) (10 + 3x)(10 – 3x) = (10)² - (3x)² = 100 - 9x² 10) (2x + 1)³ = (2x)³ + 3(2x)²(1) + 3(2x)(1)² + (1)³ = 8x³ + 12x² + 6x + 1 11) (2 – 3m)³ = (2)³ - 3(2)²(3m) + 3(2)(3m)² - (3m)³ = 8 - 12m + 18m² - 27m³
