## anonymous 5 years ago Y=x^2-6x-8 Find roots by factoring or quadratic formula if factoring doesnt work.

1. anonymous

You sure it's -8?

2. anonymous

yup, y=x^2-6x-8. Yup. Positive

3. anonymous

You're gonna want to use the quadratic formula for this one.

4. anonymous

Thought so. I dunno why, but the first time i tried, i got -38,0 and like -26,0 or something like that. i knew it was completely wrong tho...Haha

5. anonymous

Cause the only integer factors of 8 are 4 and 2, but they can't both be negative (to give -6) without the 8 being positive.

6. anonymous

Hmm..

7. anonymous

So you're gonna get non-integers

8. anonymous

So Decimals... Hopefully theyre only .5

9. anonymous

polpack will you help me?

10. anonymous

K i'll solve it.

11. anonymous

I just leave em as fractions usually

12. anonymous

but then my teachers rarely let us use calculators

13. anonymous

She's fine with us using them. she just likes us to try without them. you can play cards on our calculators..haha

14. anonymous

polpak. can you help me

15. anonymous

$x=\frac{6 \pm\sqrt{36 - 4(-8)}}{2} = 3 \pm \frac{\sqrt{68}}{2} = 3 \pm \frac{\sqrt{4\times 17}}{2} = 3 \pm \sqrt{17}$

16. anonymous

but theres no variables in that. :(

17. anonymous

those are the roots, sorry.

18. anonymous

to factor just say $$y = (x-3+\sqrt{17})(x-3-\sqrt{17})$$

19. anonymous

20. anonymous

ohh, so all i need to do is...ohh, okay...THANKS!

21. anonymous

ohh, so all i need to do is...ohh, okay...THANKS!