To prove : (ax+1ay+1)x+y(ay+2az+2)y+z(az+3ax+3)z+x=1
LHS
=(ax+1ay+1)x+y(ay+2az+2)y+z(az+3ax+3)z+x
=[a(x+1−y−1)(x+y)][a(y+2−z−2)(y+z)][a(z+3−x−3)(z+x)]
=[a(x−y)(x+y)][a(y−z)(y+z)][a(z−x)(z+x)]
=ax2−y2×ay2−z2×az2−x2
=a(x2−y2+y2−z2+z2−x2)
=a0
=1
=RHS
Hence, proved .