Factorise: a3-b3-c3-3abc.
Factorise the polynomial
Using the identity x3+y3+z3-3xyz=(x+y+z)(x2+y2+z2-xy-yz-xz)
put x=a,y=-b,z=-c
a3-b3-c3-3abc=(a-b-c)(a2+(-b)2+(-c)2-a(-b)-(-b)(-c)-(-c)a)⇒a3-b3-c3-3abc=(a-b-c)(a2+b2+c2+ab-bc+ac)
Hence, the factors of a3-b3-c3-3abc are (a-b-c)and (a2+b2+c2+ab-bc+ac).