1. (a+3)(a-1)
2. (a-3)(a+1)
3. (x+5)(x-4)
4. (m-6)(m-5)
5. (-x+3)(-x+5)
6. (-a-2)(-a-3)
7. (3x-2y)(y+2x)
8. (-4y+5x)(-3x+2y)
9. (5a-7b)(a+3b)
10. (7x-3)(4+2x)
11. (-a+b)(-4b+8a)
12. (6m-5n)(-n+m)
13. (8n-9m)(4n+6m)
14. (-7y-3)(-11+2y)
