The given relation can be written as (a2p2−2abp+b2)+(b2p2+c2−2bpc)+(c2p2+d2−2pcd)≤0 or (ap−b)2+(bp−c)2+(cp−d)2≤0 . . . (i) Since a,b,c,d and p are all real, the inequality (i) is possible only when each of factor is zero. i.e., ap−b=0,bp−c=0 and cp−d=0 or p=