(a-4b)(1/3a^2+4b^2+ab)

(a-4b)(1/3a^2+4b^2+ab)
(a-4b)(1/3a^2+4b^2+ab)

(a-4b)(1/3a^2+4b^2+ab)
(a-4b)(1/3a^2+4b^2+ab)
=a (1/3a^2+4b^2+ab)-4b (1/3a^2+4b^2+ab)
=⅓a³+4ab²+a²b-4/3 a²b-16b³-4ab²
=⅓a³-⅓a²b-16b³

(a-4b)(1/3a²+4b²+ab)
=a (1/3a²+4bv+ab)-4b (1/3av+4b²+ab)
=1/3a³+4ab²+a²b-4/3 a²b-16b³-4ab²
=1/3a³-1/3a²b-16b³