Answer
$\log _{2}\dfrac {\left( x+1\right) ^{2}}{\left( x+3\right) \left( x-1\right) }$
Work Step by Step
We use the rules of logarithms to obtain:
$2\log _{2}\left( x+1\right) -\log _{2}\left( x+3\right) -\log _{2}\left( x-1\right) =\log _{2}\dfrac {\left( x+1\right) ^{2}}{\left( x+3\right) \left( x-1\right) }$