Elementary and Intermediate Algebra: Concepts & Applications (6th Edition)

$9p^4-6p^2q^3+q^6$
Using $(a+b)^2=a^2+2ab+b^2$ or the square of a binomial, the given expression, $(3p^2-q^3)^2 ,$ is equivalent to \begin{array}{l}\require{cancel} (3p^2)^2+2(3p^2)(-q^3)+(-q^3)^2 \\\\= 9p^4-6p^2q^3+q^6 .\end{array}