PLEASE HELP 50 POINTS

Directions: Solve by finding the difference of two squares. 1. x2 - y2 =
2. x^2 - 16

3. a^2 - b^2

4. a^2 - 25

5. x^2 - 121

6. 225 - a^2

7. 400 - y^2

8. 900 - z^2

9. 4x^2 - 49

10. 16x^2 - 25

11. 36x^2 - 64

12. 64 - a^2

13. 36x^2 - 64

14. 25a^2 - 16

15. 9a^2 - 81

16. 49a^2 - 4

17. 100x^2 - 9

18. 64x^2 - 25

19. 144x^2 - 100

20. 25x^2 - 25y2