## anonymous 4 years ago 18m^2-1 factor plz!

1. anonymous

$81m^2-1$

2. anonymous

wait which one, or both

3. anonymous

both plz!

4. anonymous

if you set them to zero just have 18m^2 -1=0 18m^2 =1 m^2 = 1/18 $m = \sqrt{1/18}$

5. anonymous

so the same with the other you will have $(m - \sqrt{1/18})^{2}$ and $(m - \sqrt{1/81})^{2}$

6. anonymous

THANKZ YOUZ!

7. anonymous

8. asnaseer

@Davidjohn - I /think/ your last steps where you factorized the expressions has a mistake in it. I believe you can use the rule $$a^2-b^2=(a+b)(a-b)$$ to get:$81m^2-1=9^2m^2-1^2=(9m)^2-1^2=(9m+1)(9m-1)$

9. anonymous

@asnaseer that makes a whole lot more sense!

10. anonymous

oh yeah, i generalized that one too much, youre right

11. anonymous

but the answer would be right if expanded because it would simplify down and you could multiply them to get the same answer

12. asnaseer

glad I could help - and no worries @Davidjohn - we all make mistakes - that's what makes us human :-)

13. anonymous

ah except it would be plus or minus then, not just minus minus

14. asnaseer

$(m - \sqrt{1/81})^{2}=m^2-2\sqrt{1/81}+1/81$

15. anonymous

right my bad :) thanks for correcting

16. anonymous

Woah... the first thing you showed me was a lot easier to understand...

17. asnaseer

:)