Answer
$x=1.5$
Work Step by Step
On the RHS, apply:$\qquad \log_{a}(AB)=\log_{a}A+\log_{a}B$
$\log(x+3)=\log x+\log 3$
$\log(x+3)=\log(x\cdot 3)\qquad$
... apply $10^{(..)}$ to both sides
$ x+3=3x\qquad$...$/-x$
$ 3=2x\qquad$...$/\div 2$
$x=\displaystyle \frac{3}{2}$