Chapter 5 - Section 5.3 - Special Products - Exercise Set - Page 368: 62

$x^{16}+10x^8+25$

Using $(a\pm b)^2=a^2\pm2ab+b^2$ or the square of a binomial, the square of the given expression, $\left( x^8+5 \right)^2,$ is \begin{array}{l}\require{cancel} (x^8)^2+2(x^8)(5)+(5)^2 \\\\= x^{16}+10x^8+25 .\end{array}