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

9. 4a + (9a+3)

10. 7b + (4b - 6)

11. 8d2 + (6d2 - 4d)

12. (5x2 + 4) + (-3x2 - 4)

13. [-4x + (10 - 5x)] + 5x

14. 8 + [5 + (6 + x)]

15.

+3c - 7d

- 2c + 5d

- c + 8d

+4c - 6d

16.

3a + 8b - 5c

6a - 9b + 4c

-7a + b + 2c

17.

+6p - 3q + z

- 3p + 2q - z

- p + 00q___