Question 84 (ix)
Simplify
(a−b)(a2+b2+ab)−(a+b)(a2+b2−ab)
(a−b)(a2+b2+ab)−(a+b)(a2+b2−ab)=a(a2+b2+ab)−b(a2+b2+ab)−a(a2+b2−ab)−b(a2+b2−ab)=a3+ab2+a2b−ba2−b3−ab2−a3−ab2+a2b−ba2−b3+ab2=(a3−a3)+(−b3−b3)+(ab2−ab2)+(a2b−a2b+ab2−ab2)=0−2b3+0+0+0=−2b3
(a+b)(a2+b2−ab) =