Using properties of determinants prove that:
Taking a, b, c from C1, C2, C3
Operating R1→R1-R3, R2→R2-R3
Taking (a2+b2+c2) common from R1, R2
Operating R3→R3+R1+R2
Taking (a2+b2+c2) common from C3 �
Expanding with C3
= abc(a2+b2+c2)3×1×(1-0)
= abc (a2+b2+c2)3
Hence proved