(а+ b)^3-5(a-2b)^2+13ab=
a^3+3a^2b+3ab^2+b^3-5a^2+20ab-20b^2+13ab=
a^3+3a^2b+3ab^2+b^3-5a^2+33ab-20b^2
(а+ b)^3-5(a-2b)^2+13ab=
a^3+3a^2b+3ab^2+b^3-5a^2+20ab-20b^2+13ab=
a^3+3a^2b+3ab^2+b^3-5a^2+33ab-20b^2