I've been trying to make a system of linear equations in LaTeX for a while, I couldn't even find results on the internet. Another thing to note is everything I've tried was based on the \systeme command provided by the systeme package that everyone seems to use, I don't know if there's a better alternative to that I could use but if there is, I'd be very happy to know. I'll use this equation as an example:


By solving this equation I get to

\systeme{x-y=1, x^{2}+y^{2}=41} 

All the codes until \systeme{x=y+1,(y+1)^{2}+y^{2}} work fine, but that one really doesn't work, I've tried various different things but it always displays this error message in french

! Package systeme Error: l'inconnue "y_{-1}" a deja ete trouvee dans l'equation
<argument> ... deja ete trouvee dans l'equation !}
                                                  \fi \ifSYS_sortvariable \S...
l.78 \systeme{x=y+1,(y+1)^{2}+y^{2}}

I don't know french but by putting it in google translate I get:

! Package system Error: the unknown "y _ {- 1}" has already been found in the equation
<argument> ... already found in the equation!}
                                                  \ fi \ ifSYS_sortvariable \ S ...
l.78 \ system {x = y + 1, (y + 1) ^ {2} + y ^ {2}}

I think the problem is that y appeared twice in the equation, but that is supposed to happen, is there anything I could do besides putting y_{1} and y_{2} in the entire equation? Thanks in advance

  • 3
    \systeme is for linear systems
    – egreg
    Jun 25, 2020 at 14:11
  • Oh... What should I do/use then? Thanks for the information though Jun 25, 2020 at 14:21

1 Answer 1


I see no sensible way to align variables in nonlinear systems. Maybe the first system might have x and y aligned with each other, but what about the other two?


\newenvironment{lsystem}% left aligned system


x-y=1 \\
x=y+1 \\
x=y+1 \\


enter image description here

Why not cases? Because it would add unwanted space at its right side.

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