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

$4y^2-2y+\dfrac{1}{4}$
Using $(a\pm b)^2=a^2\pm2ab+b^2$ or the square of a binomial, the square of the given expression, $\left( 2y-\dfrac{1}{2} \right)^2,$ is \begin{array}{l}\require{cancel} (2y)^2-2(2y)\left( \dfrac{1}{2} \right)+\left( \dfrac{1}{2} \right)^2 \\\\= 4y^2-2y+\dfrac{1}{4} .\end{array}