| x^2-y^2 | (x-y)(x+y) |
| (a^2-9) | (a-3)(a+3) |
| 144-x^2 | (12-x)(12+x) |
| 1-u^2/4 | (1-u/2)(1+u/2) |
| 16-81z^4 | (2-3z)(2+3z)(4+9z^2) |
| 9x^2+12xy+4y^2 | (3x+2y)^2 |
| 25a^2+40ab+16b^2 | (5a+4b)^2 |
| 18x^2+12x+2 | 2*(3x+1)^2 |
| 9x^3+24x^2+16x | x(3x+4)^2 |
| 25a^2+20a+4 | (5a+2)^2 |
| 49x^2+14x+1 | (7x+1)^2 |
| a^2-10a+25 | (a-5)^2 |
| 4p^2-4pq+q^2 | (2p-q)^2 |
| 9u^2-48u+64 | (3u-8)^2 |
| 0.04a^2-0.12ab+0.09b^2 | (0.2a-0.3b)^2 |
| a^2-ab+b^2/4 | (a-b/2)^2 |