## Intermediate Algebra (12th Edition)

$9t^2-12st+4s^2$
Using $(a+b)^2=a^2+2ab+b^2$ or the square of a binomial, the product of the given expression, $(3t-2s)^2 ,$ is \begin{array}{l}\require{cancel} (3t)^2+2(3t)(-2s)+(-2s)^2 \\\\= 9t^2-12st+4s^2 .\end{array}