(a-4b)(0.25a²+4b²+ab)

(a-4b)(0.25a²+4b²+ab)
(a-4b)(0.25a²+4b²+ab)

(a-4b)(0.25a²+4b²+ab)
原式=0.25（a--4b)(a^2+4ab+16b^2)
=0.25(a^3--64b^3)
=0.25a^3--16b^3.

(a-4b)(0.25a²+4b²+ab)
=a³＋4ab²＋a²b－a²b－16b³－4ab²
=a³－16b³