Answer
$a=-1$
Work Step by Step
Multiplying both sides by the $LCD=
a
$, then the solution to the given equation, $
\dfrac{3}{a}-5=\dfrac{7}{a}-1
,$ is
\begin{array}{l}
1(3)-a(5)=1(7)-a(1)
\\\\
3-5a=7-a
\\\\
-5a+a=7-3
\\\\
-4a=4
\\\\
a=\dfrac{4}{-4}
\\\\
a=-1
.\end{array}