=k ... (i) In the given condition we know that a,b and c can not be zero. From Eq. (i), we get ay−bx=ck cx−az=bk bz−cy=ak Multiplying Eq. (ii) by c, we get acy −bcx=c2k Multiplying Eq. (iii) by b, we get bcx−abz=b2k Multiplying Eq. (iv) by a, we get abz−acy=a2k Adding Eq. (v), Eq. (vi) and Eq. (vii), we get acy −bcx+bcx−abz+abz −acy=k(a2+b2+c2) ⇒0=k(a2+b2+c2) Since, a,b and c are not zero. ∴k=0 Put k=0 into Eq. (ii), Eq (iii) and Eq. (iv), we get *1) ay=bx⇒