1. a(b+c) = ab + ac
2. (a+b)2 = a2 + 2ab + b2
3. (a-b)2 = a2-2ab + b2
4. (a+b)2 = (a-b)2 + 4ab
5. (a-b)2 = (a+b)2 – 4ab
6. (a-b) (a+b) = a2 – b2
7. (a+b)3 = a3 + 3ab(a+b) + b3
8. (a-b)3 = a3 – 3ab(a-b) – b3
9. a3 + b 3 = (a+b) (a2 – ab + b2)
10. a3 – b 3 = (a-b) (a2 + ab + b2)
11. (a3 – b3) / (a2 + ab + b2) = a-b
12. (a3 + b3) / (a2 – ab + b2) = a+b
hi good website for all especially for youth, teachers, parents and the