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

$4x^2+20xy+15y^2$
Using $(a\pm b)^2=a^2\pm2ab+b^2$ or the square of a binomial, the square of the given expression, $(2x+5y)^2 ,$ is \begin{array}{l}\require{cancel} (2x)^2+2(2x)(5y)+(5y)^2 \\\\= 4x^2+20xy+15y^2 .\end{array}