Chapter 5 - Section 5.3 - Special Products - Exercise Set - Page 367: 32

$16-s^2$

Using $(a+b)(a-b)=a^2-b^2$ or the special product of the sum and difference of like terms, the product of the given expression, $ (4+s)(4-s) ,$ is \begin{array}{l}\require{cancel} 4(4)-s(s) \\\\= 16-s^2 .\end{array}