Ответ:

а) \(3ab^3(a^2-ab+b^2)=3a^3b^3-3a^2b^4+3ab^5\).

б) \(\frac12ab(6a^3-4ab^2+1)=3a^4b-2a^2b^3+\frac12ab\).

в) \(\frac1{12}m^2n^2(2m^2-3mn+4n^2)=\frac16m^4n^2-\frac14m^3n^3+\frac13m^2n^4\).

г) \(\frac18mn(8m^3-7m^2n+1)=m^4n-\frac78m^3n^2+\frac18mn\).

Ответ: а) \(3a^3b^3-3a^2b^4+3ab^5\); б) \(3a^4b-2a^2b^3+\frac12ab\); в) \(\frac16m^4n^2-\frac14m^3n^3+\frac13m^2n^4\); г) \(m^4n-\frac78m^3n^2+\frac18mn\).