Answer
$4n^2-49$
Work Step by Step
Using $(a+b)(a-b)=a^2-b^2$ or the product of the sum and difference of like terms, the product of the given expression, $
(-7+2n)(7+2n)
,$ is
\begin{array}{l}\require{cancel}
(2n-7)(2n+7)
\\\\=
(2n)^2-(7)^2
\\\\=
4n^2-49
.\end{array}
