This is in Maxima.

```
Maxima 5.33.0 http://maxima.sourceforge.net
using Lisp ECL 12.12.1
Distributed under the GNU Public License. See the file COPYING.
Dedicated to the memory of William Schelter.
The function bug_report() provides bug reporting information.
(%i1) load("solve_rat_ineq");
(%o1) /Users/.../sage/local/share/maxima/5.33.0/share/solve\
_rat_ineq/solve_rat_ineq.mac
(%i2) solve_rat_ineq((x^2-9)/(x-3) >= 0);
(%o2) [[x >= - 3]]
```

That said, Maxima (and Sage and lots of other things) do simplify `x^2/x`

to be just `x`

, so I am not 100% sure it's not intended behavior. Anyway, I agree it would be better to not have the 3, so I've reported it at Maxima bug 2804.