C-03-Q114mediumsingle_mcqx2+y2+z2−xy−yz−zx=?x^2 + y^2 + z^2 - xy - yz - zx = ?x2+y2+z2−xy−yz−zx=?a12[(x−y)2+(y−z)2+(z−x)2]\frac{1}{2}[(x-y)^2 + (y-z)^2 + (z-x)^2]21[(x−y)