# need help with geometry

Discussion in 'General Off-Topic Chat' started by Zenith94, Nov 21, 2008.

# need help with geometry

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1. ### Zenith941337 h4x0r f0r t3h w1nz

Member
1
Jul 22, 2008
ok this is really pissing me off now i need to find the y-intersept of a segment without a graph (its that y=mx+b thing) i basically need to find B so say I have a segment that starts at (2,5) and ends (8,9) how to do i find B? i dont know my teachers are retarded

Member
1
Jul 22, 2008
hurry up

3. ### MystikEkoezGBAtemp Fan

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1
Sep 5, 2006
Georgia
Use the two set of points to find the slope. (m)
Then plug in one of the set of points and solve for b.

4. ### BangerMe > | | < You ..Wanna Line dance?

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1
Oct 31, 2007

Yet you are the one that can not figure it out?

Member
1
Sep 5, 2006
Georgia
Zing!

6. ### *~ArcNewbie

Newcomer
1
Jun 11, 2008
First you have to find the slope(m). To find the slope you take two points[(2,5) and (8,9)] and make it so (9-5)/(8-2) which is a slope of 2/3.
Substitute that in for m.[y=2/3x+b]
Next Substitute one of the two points into the equation. [5=(2/3)(2)+b]
Solve for b. [5-(4/3)=b]
Simplify. [11/3=b]

7. ### MystikEkoezGBAtemp Fan

Member
1
Sep 5, 2006
Georgia
. . . If you tell him how to do it, he won't learn anything.
Way to fail. I hope someone comes and chops off your nuts so you won't have the ability to reproduce thus improving the future of the universe.

8. ### DarkLGWow One Shiny Ribbon!!!!

Member
1
Jun 21, 2007
Indiana
That's how you learn stuff by showing how to do it,not by figuring it out for yourself cause then you won't know if your right.

Member
2
Jul 6, 2008
Lols, that sounded really mean

10. ### Sevenoh hell no

Member
2
Jun 22, 2007
Well, that's why you do it wrong first, then later when people actually give him the right answer, he'll see why he's wrong and he'll be less likely to make the same mistake twice.

Not knowing if you're right is moot. If you have an answer, give it, and if you're wrong, well, that's too bad, you can learn from mistakes. No one said he had to be right.

Banned
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Jun 20, 2008

12. ### nin10doGBAtemp Fan

Member
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Dec 22, 2007
UK
FAIL:

this is what happens if you don't read the question carefully. the segment STARTS at 2,5 and ENDS at 8,9.

that means it doesn't pass through the y axis therefor there is no Y intercept.

13. ### MystikEkoezGBAtemp Fan

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Sep 5, 2006
Georgia
ROFLMAO. Owned.

14. ### Zenith941337 h4x0r f0r t3h w1nz

Member
1
Jul 22, 2008
i mean those are 2 points it is a LINE i messed up

and when i said my teachers are retarded i mean they CANT teach

15. ### Zenith941337 h4x0r f0r t3h w1nz

Member
1
Jul 22, 2008
thanks dude i just didnt know i could substitue the y for one of the two points in y=2/3x+b

that clears so much up

16. ### xcaliburGbatemp's Chocolate Bear

Member
2
Jun 2, 2007
Sacred Heart
You'll never learn maths untill you practice and I really suggest that you do another question on your own.
Arc did the question right and nin10doh is a tard for reading too much into the wording of the question.
He can't do a simple maths question yet you trust his english skills completely?

17. ### nin10doGBAtemp Fan

Member
1
Dec 22, 2007
UK
hey i was merly pointing out that being able to express yourslef clearly is important. knowing something but not able to put it into proper words can land you a low grade.

18. ### nin10doGBAtemp Fan

Member
1
Dec 22, 2007
UK
i find this way easier:

y=mx+c ------eq1 put the first coordinates in here
y=mx+c ------eq2 put the second coordinates in here.

5=2m+c -------eq1
9=8m+c -------eq2

you have two equations and two unkowns. there is a finite set of answers. simultaneously solve them.
multiply eq1 with 8 and eq2 with -2 to get:

40=16m+8c -----eq1
-18=-16m-2c -----eq2

adding the two equations together gives:

22=6c
c=22/6
simplify
c=11/3