| (a-b)(c+d) | ac+ad-bc-bd |
| (a-1)(a-5) | a^2-6a+5 |
| (a+2)(a+2) | a^2+4a+4 |
| (a-b)(a-1) | a^2-a-ab+b |
| (a+5)(a-5) | a^2-25 |
| (a-3)(a-5) | a^2-8a+15 |
| (a-3)(a+5) | a^2+2a-15 |
| (a+3)(a-5) | a^2-2a-15 |
| (a+3)(a+5) | a^2+8a+15 |
| (a-3b)(a+3b) | a^2-9b^2 |
| (2a-3b)(2a+3b) | 4a^2-9b^2 |
| (2a+3b)(2a+3b) | 4a^2+12ab+9b^2 |
| (a-1)(a-2) | a^2-3a+2 |
| (a+5)(a-b) | a^2-ab+5a-5b |
| (a-3)(2a+3) | 2a^2-3a-9 |
| (2a-3)(a+3) | 2a^2+3a-9 |