Question

АЛГЕБРА СРОЧНО 7 КЛАСС ДАЮ 100 БАЛЛОВ

Answer 1

Напоминаю формулы

a^3 - b^3 = (a - b)(a^2 + ab + b^2)

a^2 - b^2 = (a - b)(a + b)

(a  + b)^2 = a^2 + 2ab + b^2

(a  -  b)^2 = a^2 - 2ab + b^2

3.

9y² - 25 = (3y)² - 5² = (3y - 5)(3y + 5)

4a - a³ = a(4 - a²) = a(2 - a)(2 + a)

-2a² + 4ac - 2c² = -2(a² - 2ac + c²) = -2(a - c)² = -2(a - c)(a - c)

4.

bc + b² - 3c - 3b = b(b + c) -3(b + c) = (b - 3)(b + c)

b = 3.7  c = -4.7

(3.7 - 3)(3.7 - 4.7) = 0.7*(-1) = -0.7

5.

16 - (y + 1)² = 4² - (y + 1)² = (4 - (y+1))(4 + (y + 1)) = (3 - y)(5 + y)

1/27a³ - x³ = (1/3a)³ - x³ = (1/3a - x)((1/3a)² + 1/3a*x + x²) = (1/3a - x)(1/9a² + 1/3ax + x²)

a⁴ - 16b⁴ = (a²)² - (4b²)² = (a² - 4b²)(a² + 4b²) = (a - 2b)(a + 2b)(a² + 4b²)

3c - c² - 3a + a² = 3c - 3a - (c² - a²) = 3(c - a) - (c - a)(c + a) = (c - a)(3 - c - a)