1. (x-b)(x+b)= x²-b²

2. (a-b)(a+b)=a²-b²

3. (m-k)(m+k)=m²-k²

4. (a+b)(a-b)=a²-b²

5. (y-3)(y+3)=y²-3³

6. (x-7)(x+7)=x²-7²

7. (6-a)(6+a)=6²-a²

8. (10-t)(10+t)=10²-t²

9. (4+d)(4-d)=4²-d²

10. (b+3)(b-3)=b²-3²

11. (7+y)(7-y)=7²-y²

12. (4-y)(4+y)=4²-y²

13. (8-y)(y+8)=8²-y²

14. (12-z)(12+z)=12²-z²

15. (1/2-y)(1/2+y)=(1/2)²-y²

16. (1/4-x)(1/4+x)=(1/4)²-x²

17. (y-3/5)(y+3/5)=y²-(3/5)²

18. (21-a)(21+a)=21²-a²

19. (92-x)(92+x)=92²-x²