Question

(x-7)³ (8-в)³ (11-y)³ помогите пж​

Answer 1

По формуле нахождения куба разности и суммы двучлена:

(a + b)³ = a³ + 3a²b + 3ab² + b³

(a - b)³ = a³ - 3a²b + 3ab² - b³

Решим по этой формуле все три задачи:

1) (x - 7)³ = x³ - 3 ⋅ x² ⋅ 7 + 3 ⋅ x ⋅ 7² - 7³ =

= x³ - 21x² + 147x - 343

2) (8 - b)³ = 8³ - 3 ⋅ 8² ⋅ b + 3 ⋅ 8 ⋅ b² - b³ =

= 512 - 192b + 24b² - b³

3) (11 - y)³ = 11³ - 3 ⋅ 11² ⋅ y + 3 ⋅ 11 ⋅ y² - y³ =

= 1331 - 363y + 33y² - y³