I've added a new solution box to the question whenever you divide by an expression so you have to include the domain condition as part of your answer.
It's formatted using a table isn't isn't ideal especially as tabbing from one box to another goes in an unintuitive order, but it seemed better than creating a lot more divs and trying to line them up.
I still can't get rid of the old merge as part of my pull request.
Merge branch 'graph-legend'
Create new solution box for domain
Ensure domain box only shows when needed and accepts the correct answer
Rearrange solution boxes
Add hints to explain the domain
Addresses issue #43362
Redone this pull request #43433