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