Answer
$-1$
Work Step by Step
Step 1. Rewrite the equation as $log_6[(x+4)(x+3)]=1 \longrightarrow log_6(x^2+7x+12)=1$
Step 2. Thus $x^2+7x+12=6\longrightarrow x^2+7x+6=0\longrightarrow (x+1)(x+6)=0\longrightarrow x=-1,-6$.
Step 3. Check answers, only $x=-1$ fits the original equation.