Are these answers correct?

Question

Factor Completley:

1. x^2+21x+20__
(x+20)(x+1)__

2. 12x^4y^2-8x^3y^4+16x^2y^2__
4x^2y^2(3x^2-2xy^2+4)__

3. 3x^2+9x-30__
3(x+5)(x-2)__

4. b^2-14b+24__
(b-12)(b-2)__

5. x^4y+5x^3y^2+x^2y^3__
x^2y(x^2+5xy+y^2)__

6. 4x^2-8x+20__
not factorable__

7. 7x^2y^2-21x^2y+7xy__
7xy(xy-3x+1)__

8. 5m^2-16m+3__
(5m-1)(m-3)__

9. 3x^2-24x-99__
3(x+3)(x-11)__

10. 2x^2-10x-4__
Not Factorable__

11. x^2-3x+4__
Not Factorable__

12. 6x^2+11x+4__
(3x+4)(2x+1)__

13. 21x^4-14x^3+7x^2__
7x^2(3x^2-2x+1)__

14. 8x^2+10x-3__
Not Factorable__

15. 6x^3-15x^2+3x__
3x(2x^2-5x+1)__

16. x^2+5x+7__
Not Factorable__

17. 2x^2-7x+3__
(2x-1)(x-3)__

18. 10x-25-x^2__
-(x-5)^2__

19. 16y^2+16y+4__
4(2y+1)^2__

20. -x^2-3xy+18y^2__
-(x-3y)(x+6y)__

21. x^2-9x+20=0__
x= 5, or 4__

22. x^3-7x^2=10x^2__
x=0, or 17__

23. x^2+8x=0__
x=0, -8__

24. 2x^2-9x+10=0__
x= 5/2, 2__

I really REALLY need these checked so if you would i would greatly appreciate it. The first person to actually help me, I will choose as the best answer. This is a take home quiz that I have to do for my algebra class and I m not so sure about my answers. Thank you :]

Answer 1

1 - 5. correct

6 can be factored 4(x^2 - 2x + 5), but no further.

7 - 9. correct

10 can be factored to 2(x^2 - 5x - 4)

11 - 13. correct

14. 8x^2 + 10x - 3 = (4x - 1)(2x + 3)

15 - 24. correct

Good job!