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

$(5z+y)^2$
The given expression, $25z^2+10zy+y^2 ,$ is a perfect square trinomial since the first and third terms are both perfect squares and the middle term is twice the product of the square roots of the first and third terms. Hence, the complete factored form is \begin{array}{l} (5z+y)^2 .\end{array}