г) за ⋅ 4b² - 0,8b ⋅ 4b²- 2ab ⋅ 3b + b ⋅ 3b²- 1.

г) $$3a \cdot 4b^2 - 0,8b \cdot 4b^2 - 2ab \cdot 3b + b \cdot 3b^2 - 1 = 12ab^2 - 3,2b^3 - 6ab^2 + 3b^3 - 1 = (12ab^2 - 6ab^2) + (-3,2b^3 + 3b^3) - 1 = 6ab^2 - 0,2b^3 - 1$$.

Ответ: $$6ab^2 - 0,2b^3 - 1$$