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:
