#### Answer

$7$

#### Work Step by Step

Using $(a+b)(a-b)=a^{2}+b^{2}$, or the Distributive Property, and the properties of radicals, the given expression, $
(\sqrt{11}-2)(\sqrt{11}+2)
,$ simplifies to
\begin{array}{l}\require{cancel}
(\sqrt{11})^2-(2)^2
\\\\=
11-4
\\\\=
7
.\end{array}