a3+b3+c3-3abc = 0
=> (a+b+c)(a2+b2+c2-ab-bc-ca) = 0
=> a+b+c = 0 (or) a2+b2+c2-ab-bc-ca = 0
a2+b2+c2-ab-bc-ca = 0 => 2(a2+b2+c2-ab-bc-ca) = 0
=> (a-b)2+(b-c)2+(c-a)2 = 0 => a-b = b-c = c-a = 0 => a=b=c
If a3+b3+c3-3abc = 0, then the possibilities are
a+b+c = 0 (2) a2+b2+c2= ab+bc+ca (3) a=b=c