Answer
$|x-4|\geq 6$
Work Step by Step
The statement "$x$ is at least $6$ units from $4$" can be written as an inequality as follows:
$$
|x-4|\geq 6
$$
Notice that we take the absolute value sign because we do not care whether the difference of $4$ is positive or negative. This can also be seen as a measure of distance -- $x$ and $4$ are $6$ units apart.