1 (x-2)^2-2
2 (a+b)^2-ab
3 (a2-ab+1/4b2)+(3/4b2-3b+3)+(c2-2c+1)=0
(a-1/2b)2+3/4(b-2)2+(c-1)2=0;
a=1,b=2,c=1,a+b+c=4