Answer
$\dfrac{7}{x+y}$
Work Step by Step
Factoring the expressions and then cancelling the common factors between the numerator and the denominator result to
\begin{array}{l}
\dfrac{7x-7y}{x^2-y^2}
\\\\=
\dfrac{7(x-y)}{(x+y)(x-y)}
\text{...cancel $(x-y)$}
\\\\=
\dfrac{7}{x+y}
.\end{array}