Answer
$x\leq3$
Work Step by Step
[ ] is equivalent to the greater/less than and equal to $\leq$ and $\geq$ signs
( ) is equivalent to the greater/less than $\lt$ and $\gt$ signs
Thus from the information given x is less than or equal to 3
$x\leq3$
The other information given by the interval notation is x is greater than negative infinity
In this case we don't have to write out $-\infty$$\lt$x because in writing just $x\leq3$ it includes all numbers below or equal to 3
