How to prove that these two languages are regular, or not regular?
Hints:

One of the two languages is not regular. It is the one that forces you
to count beyond 10 to decide whether some strings are in the language.
Regular languages are not very good at counting without bound.

However, the use of the pumping lemma to prove it requires that you start from a
string in the language where $n$ is as close to $m$ as permitted by
the definition of the language, and that you pump out rather than in,
i.e. remove the only $w$ of the $xwy$ decomposition of the string,
rather than inserting more copies of $w$.

Alternatively, you can prove that the reverse of the language is not
regular, if you know about closure properties.