Answer
$\frac{9}{2}=4.5$
Work Step by Step
Step 1. Rewrite the equation as $log_{a}[(x-1)(x+3)]=log_{a}[(x-2)(x+6)] \longrightarrow log_{a}(x^2+2x-3)=log_{a}(x^2+4x-12)$
Step 2. Thus $x^2+2x-3=x^2+4x-12\longrightarrow 2x=9\longrightarrow x=\frac{9}{2}=4.5$.
Step 3. Check answers, $x=\frac{9}{2}=4.5$ fits the original equation.