1. (A + B)2 = A2 + 2AB + B2
2. (A – B)2 = A2 – 2AB + B2
3. A2 – B2 = (A + B)(A – B)
4. (A + B)3 = A3 + 3A2B + 3AB2 + B3
5. (A – B)3 = A3 – 3A2B + 3AB2 – B3
6. A3 + B3 = (A + B)(A2 – AB + B2)
7. A3 – B3 = (A – B)(A2 + AB + B2)
8. (A + B + C)2 = A2 + B2 + C2 + 2AB + 2AC + 2BC
9. (A + B – C)2 = A2 + B2 + C2 + 2AB – 2AC – 2BC
10. A3 + B3 + C3 – 3ABC = (A + B + C)(A2 + B2 + C2 – AB – AC – BC)
11. (A + B + C)3 – A3 – B3 – C3 = 3(A + B)(B + C)(A + C)
Lưu ý:
(a – b)2 = (b – a)2
(a – b)3 ≠ (b – a)3
Tiêu đề: 7 hang dang thuc dang nho
