#### Answer

$(-\infty, 1]$
Refer to the image below for the graph.

#### Work Step by Step

The inequality is "x is less than or equal to 1." This inequality includes all numbers from 1 to its left.
This means that the equivalent interval notation of this inequality will have:
(i) negative infinity and parenthesis on the left; and
(ii) 1 and bracket on the right
Thus, the interval notation is:
$(-\infty, 1]$
To graph this interval, plot a hole (or hollow dot) at $1$, then shade the region to its left.
(refer to the attached image in the answer part above)