4x² -12xy+9y² +x² -4xy+4y² +2|x-y|=2
(2x-3y)² +(x-2y)² +2| x-y|=2
(2x-3y)² + (x-2y)²+2(x-y)-2=0
|2x-3y| + |x-2y| +2x-2y-2=0
-2x+3y-x+2y+2x-2y-2=0
3y-x-2=0
3y-x=2
-x=2-3y
x=3y-2
|2x-3y|=0 ∧ |x-2y|=0 ∧ 2|x-y|=0
2x-3y=0 3y-2-2y=0 x-y=0
2(3y-2)-3y=0 y-2=0 3y-2-y=0
6y-4-3y=0 y= 2 2y-2=0
3y-4=0 x=3*2-2 2y=2
3y= 4 x=6-2=4 y=1
y=4/3 x=3*1-2=3-2=1
=> x=3*4/3 -2= 4-2=2
S={(2;4/3);(4;2);(1;1)}
