Answer
$6a^3+7a^2b+4ab^2+b^3$
Work Step by Step
Using the Distributive Property, the given expression, $
(2a+b)(3a^2+2ab+b^2)
,$ is equivalent to
\begin{array}{l}\require{cancel}
2a(3a^2)+2a(2ab)+2a(b^2)+b(3a^2)+b(2ab)+b(b^2)
\\\\=
6a^3+4a^2b+2ab^2+3a^2b+2ab^2+b^3
\\\\=
6a^3+(4a^2b+3a^2b)+(2ab^2+2ab^2)+b^3
\\\\=
6a^3+7a^2b+4ab^2+b^3
.\end{array}
