20 POINTS PLS HELP
1. -2x + 4x2 - 7 - x2 + 7 - 8x

2. 7ab - bc - 4ab - 5bc

3. 3x2 - 5x + 7 + 2x2 + 3x - 9

4. 3r + 2z + 9t + 4r - 5s + t

5. -5xy + 7wz - xy - 5wz

6. 4a - 6b

7. 9a - 3b

8. (-6m + n) + (-4m - 5n)

9. (9x2 + 5) + (-2x2 - 8) + (x2 - 3)

10. 4a + (9a+3)

11. 7b + (4b - 6)

12. 8d2 + (6d2 - 4d)

13. (5x2 + 4) + (-3x2 - 4)

14. [-4x + (10 - 5x)] + 5x

15. 8 + [5 + (6 + x)]

16.

+3c - 7d

- 2c + 5d

- c + 8d

+4c - 6d

17.

3a + 8b - 5c

6a - 9b + 4c

-7a + b + 2c

18.

+6p - 3q + z

- 3p + 2q - z

- p + 00q__