## Introductory Algebra for College Students (7th Edition)

$25x^2+20x+4$
Using $(a+b)^2=a^2+2ab+b^2$ or the square of a binomial, the square of the given expression, $(5x+2)^2 ,$ is \begin{array}{l}\require{cancel} (5x)^2+2(5x)(2)+(2)^2 \\\\= 25x^2+20x+4 .\end{array}