Answer
$(-\infty, 8]$
Refer to the graph below.
Work Step by Step
The conjunction "or" means union.
Recall:
The union of sets $A$ and $B$, denoted by $A\cup B$, is the set that contains the combined elements of $A$ and $B$.
$x\le1$ includes all real numbers less than or equal to $1$
In interval notation, the set is $(-\infty, 1].$
$x\le8$ includes all real numbers less than or equal to $8$.
In interval notation, the set is $(-\infty, 8].$
Thus, the union of the two given sets is $(-\infty, 1] \cup (-\infty, 8]$, which when simplified becomes $(-\infty, 8]$.
To graph this solution set, plot a solid dot at $8$ then shade the region to its left.
Refer to the graph above.