Answer
$x-49$
Work Step by Step
Using $(a+b)(a-b)=a^2-b^2$, or the special product of the sum and difference of like terms, the given expression, $
(\sqrt{x}+7)(\sqrt{x}-7)
,$ simplifies to
\begin{array}{l}\require{cancel}
(\sqrt{x})^2-(7)^2
\\\\=
x-49
.\end{array}
Note that all variables represent positive real numbers.
