کدامیک از نامساویهای زیر همارز «${{x}^{2}}+{{y}^{2}}+1\ge xy+x+y$» است؟
1 )
${{(x-y)}^{2}}+{{(x+1)}^{2}}\ge {{(y-1)}^{2}}$
${{(x-y)}^{2}}+{{(x-1)}^{2}}+{{(y-1)}^{2}}\ge 0$
3 )
${{(x-y)}^{2}}+{{(x+1)}^{2}}+{{(y+1)}^{2}}\ge 0$
4 )
${{(x+y)}^{2}}+{{(x-1)}^{2}}+{{(y-1)}^{2}}\ge 0$