Answer
$\varnothing$.
The graph is shown below.
Work Step by Step
The given compound inequality is
$x\gt3$ and $x\lt-1$.
First graph and then take the intersection of the two inequality.
The graph is shown in the image file.
We can write the compound inequality.
$x\gt3$ as $(3,\infty)$ and $x\lt-1$ as $(-\infty,-1)$
The intersection is
$(-\infty,-1)\cap(3,\infty)=\varnothing$.