Răspuns :
Mai era ceva de genul (sistem ) :
[tex] \left \{ {{x+y=2} \atop {x-y=-2}} \right. [/tex]
_____________________________________
x / = 0
x=0
[tex] \left \{ {{x+y=2} \atop {x-y=-2}} \right. [/tex]
_____________________________________
x / = 0
x=0