## treydwg 2 years ago Can I factor this by grouping?

1. treydwg

25b^2+10b+1?

2. treydwg

Can I factor this by grouping? 25b^2+10b+1?

3. chmvijay

5b+1

4. chmvijay

b=-1/5

5. whpalmer4

Prime factors of 25 are 5 and 5 so we'll have (5x + a)(5x+b). Multiply that out and you get \[(5x+a)(5x+b) = 25x^2 + 5ax + 5bx + ab\] To make that look like your equation, a and b have to = 1.

6. rizwan_uet

25b^2+10b+1 multiply 25 with 1 you will get 25. now write 10 as the sum of two numbers such that the addition of those numbers result in 10 and the product of those numbers result in 25

7. treydwg

I got b(5b+1) 1(b+1) but that does not look correct?

8. whpalmer4

No, (5b+1)(5b+1) is what you want.

9. chmvijay

(5b+1) and (5b+1) you correct it once again

10. treydwg

5b+1)^2?

11. nitz

yes...

12. treydwg

Thanks

13. treydwg

t(4t+1)=0? I got t=0, -1/4

14. nitz

ya

15. treydwg

Alright cool! Thanks

16. nitz

welcome......

17. Hero

Well, no one really did it the correct way.

18. rizwan_uet

25b^2+10b+1 25b^2 +5b+5b+1 5b(5b+1)+1(5b+1) (5b+1)(5b+1) (5b+1)^2

19. whpalmer4

No, some of us did it in a way that shows why grouping works :-)

20. chmvijay

25b25b+5b+1=0 5(5b+1)+1(5b+1)=0 (5b+1)2=0 5b+1=0 5b=-1 b=-1/5

21. Hero

Yes, but you forgot to show the process, which is also important as well @whpalmer4. The question was "How do you factor by grouping?". Showing why it works is fine. Showing the process is equally important.