Răspuns :
x=y-1 x=1-y x=1-y x=1-y x=1-y x=1-o x=1
y-1+2y=-1 3y-1=-1 3y= -1+1 3y=0 y=o y=o y=0
y-1+2y=-1 3y-1=-1 3y= -1+1 3y=0 y=o y=o y=0