Chapter 5 - Section 5.3 - Special Products - Exercise Set - Page 367: 40

$m^6-16$

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, $ (m^3+4)(m^3-4) ,$ is \begin{array}{l}\require{cancel} m^3(m^3)-4(4) \\\\= m^6-16 .\end{array}