The result obtained when we multiply a6−b6 with the product of a2+ab+b2 and a−b is
a9−a6b3−a3b6+b9
We shall first find the product of a2+ab+b2 and a−b.
(a2+ab+b2)(a−b)
= a2(a−b)+ab(a−b)+b2(a−b)
= a3−a2b+a2b−ab2+b2a−b3
= a3−b3
Now, we shall multiply a6−b6 with the product obtained, i.e. a3−b3.
(a6−b6)×(a3−b3)
= a6(a3−b3)−b6(a3−b3)
=a9−a6b3−a3b6+b9