Выражение ( 4 a 4 − 3 b ) ⋅ 2 b − 3 b ⋅ ( 9 a 4 − 4 b )

=8b*a^4 - 6b^2 - 27b*a^4 + 12b^2= -19b*a^4 + 6b^2= -b(19a^4 - 6b)

(4a^4 − 3b )⋅2b − 3b⋅(9a^4 − 4b) =
= 8a^4b - 6b^2 -27a^4b + 12b^2 = -19a^4b + 6b^2 = b(6b - 19a^4)