The third power of a + the third power of B=

The third power of a + the third power of B=

a3+b3=a3+(a2b-a2b)+(ab2-ab2)+b3
= (a3+a2b)+(ab2+b3)-(a2b+ab2)
=a2(a+b)+b2(a+b)-ab(a+b)
=(a+b)(a2-ab+b2)