(square of 2A + cubic of 3b) (cubic of 3B - square of 2a)

(square of 2A + cubic of 3b) (cubic of 3B - square of 2a)

(square of 2A + cubic of 3b) (cubic of 3B - square of 2a)
=(the third power of 3B + the square of 2a) (the third power of 3B - the square of 2a)
=9b^6-4a^4