Disagree that it's a dupe, the question is tagged systeme so presumably the asked is looking for an answer using that package. This isn't addressed in the linked question.
– Scott H.Nov 24 '19 at 17:24
@ScottH. -- When selecting a tag, one usually types the first few letters and is provided with optional "matches". If one seems suitable, the poster usually accepts it without thinking very much. There is an existing tag "systeme", but no "system", so I conjecture the OP simply accepted what was offered without realizing the implication. Only the OP can say for sure, so this question may indeed be a duplicate.
– barbara beetonNov 25 '19 at 17:32
@barbara Quite possible. Since it doesn't look like the asker has any intention of engaging to clarify, I'm happy with that interpretation.
– Scott H.Nov 26 '19 at 00:14
@ScottH. -- Let's wait a day or two, and if no clarification comes along, I'll vote to close as a dupe.
– barbara beetonNov 26 '19 at 15:01
rcasesenvironment frommathtools. – Bernard Nov 24 '19 at 15:20systemeso presumably the asked is looking for an answer using that package. This isn't addressed in the linked question. – Scott H. Nov 24 '19 at 17:24