Answer
$9k^2+6kq+q^2$
Work Step by Step
Use special products to multiply the given expression, $
(3k+q)^2
.$
Using $(a+b)^2=a^2+2ab+b^2$ or the square of a binomial, the product of the expression above is
\begin{array}{l}\require{cancel}
(3k)^2+2(3k)(q)+(q)^2
\\\\=
9k^2+6kq+q^2
.\end{array}