с алгеброй заплачу если ответите​

1. a(b +7) = ab + 7a

2. 2y(y^3 - 4) = 2y^4 - 8y

3. (y^3 - 15y) * (-4y^2) = -4y^6 + 60y^3

4. 4b + 5(b - 12) = 4b + 5b - 60 = 9b - 60 = 3(3b - 10)

5. 3(y - 5) + 5(y + 6) = 3y - 15 + 5y + 30 = 8y + 15

6. 5 - 2x = 11 - 7(x + 2)

5 - 2x = 11 - 7x + 14

-2x + 7x = 11 - 5 + 14

5x = 20

x = 20:5

x = 4

7. Добавлю фото: