Adding Polynomials

Simplify the following expressions:

1. $(7b^2-7b-10)+(9b^2-3b-5)$

2. $(8a^2+10a-15)+(9a^2-9b+10)$

3. $(6x^2-7x+10)-(4x^2+8x+8)$

4. $10b-b^2+3b-10+b^2$

5. $(c^3+2c^2+c+1)+(4c^3+5c-3)$

6. $(x^4+x+15)-(x^3-x^2-7x+18)$

7. $(-17z-89)+(z^2+6z-10)$

8. $(3c^2+7n+8)-(6t^2+6c-3n+4)$

9. $(6x^3+62)-(x^3-x^2-x-92)$

10. $(7x^2-8x-9y+19)-(6x^2-9y^2-8x+7y)$

11. $(6g^2+5g-9p+9)+(-2g^2-6g-2)$

12. $(6y+7x+10)-(6y^2+4x-20)$