The simplified forms of the expressions are:
- For the first expression:
\[
\frac{x - 1}{3(x - 4)}.
\]
- For the second expression:
\[
\frac{x(x - 7)}{x - 1}.
\]
Thus, the final answers are:
\[
\boxed{\frac{x - 1}{3(x - 4)}}
\]
and
\[
\boxed{\frac{x(x - 7)}{x - 1}}.
\]