| x2 |
| x-2 |
| 4 |
| 2-x |
| x-2 |
| 2x |
| a |
| b+c+d |
| b |
| a+c+d |
| c |
| a+b+d |
| d |
| a+b+c |
| x+1 |
| 4x2-4x+1 |
| x2+x |
| 2x-1 |
| 1 |
| x |
| x |
| y |
| y2 |
| x |
| x2 |
| x+2 |
| 地 |
| x+2 |
| x-2 |
| x |
| x2 |
| x-2 |
| x |
| 2-x |
| a2-2ab+b2 |
| ab |
| a |
| b |
| b |
| a |
| 2a |
| a+1 |
| 2 |
| a+1 |
| y2-4y+4 |
| 2y-6 |
| 1 |
| y+3 |
| 12-6y |
| 9-y2 |
| xy |
| x2+2xy+y2 |
| x2-xy |
| x+y |
| 2x |
| x2-9 |
| 1 |
| 3-x |
| 2 |
| x2+6x+9 |
| x2 |
| x+1 |
| a2 |
| a-b |
| b2 |
| b-a |
| a+b |
| a-b |