Chapter 5 - Section 5.3 - Special Products - Exercise Set - Page 368: 53

$16x^4-8x^2+1$

Using $(a\pm b)^2=a^2\pm2ab+b^2$ or the square of a binomial, the square of the given expression, $( 4x^2-1 )^2,$ is \begin{array}{l}\require{cancel} (4x^2)^2-2(4x^2)(1)+(1)^2 \\\\= 16x^4-8x^2+1 .\end{array}