# Making a formula in excel

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### #1 [Lady♥Ada]

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# Making a formula in excel

Posted 19 January 2009 - 09:52 PM

I'm in eleventh grade and im taking discrete math, the teacher asked us to make a spreadsheet of this formula in excel:
......................... _______ .......
......x=.... - b ± √ b² - 4ac .......
....._________________ .......
........................ 2a ...................

As you can see this is the cuadratic and i dont know anything about this (or anything else) on Excel... a little help?, im not asking you guys to do it for me, just some pointers.
Thank you. ;]

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## Replies To: Making a formula in excel

### #2 [Lady♥Ada]

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## Re: Making a formula in excel

Posted 19 January 2009 - 10:29 PM

I'm in eleventh grade and im taking discrete math, the teacher asked us to make a spreadsheet of this formula in excel:
......................... _______ .......
......x=.... - b ± √ b² - 4ac .......
....._________________ .......
........................ 2a ...................

As you can see this is the cuadratic and i dont know anything about this (or anything else) on Excel... a little help?, im not asking you guys to do it for me, just some pointers.
Thank you. ;]
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### #3 bodom658

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## Re: Making a formula in excel

Posted 19 January 2009 - 10:38 PM

someone want to move this?

I'd recommend looking up inputing functions either in the MS documentation or by doing a google search. as far as i know, you just tell it which column is which variable, then click and drag the black box in your cell.

u should be able to select a cell, and do something like"
(-A:1 + sqrt(B:1*B:1 - 4*A:1*C:1))/(2*A:1)

for column D and the similar quadratic formula but switch up the sign for column E

good luck
Hopefully i've said something useful.

~Bodom
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### #4 Martyr2

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## Re: Making a formula in excel

Posted 19 January 2009 - 10:43 PM

Kritzia, it is not advised to post your question in more than one forum. We can't have redundant posts lurking around and clutter up the board. So please, in the future, don't post your question twice. People see it often no matter where you post it. They will move it if it needs to be in another forum and you will get answers rather quick.

Thanks a bunch!
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### #5 [Lady♥Ada]

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## Re: Making a formula in excel

Posted 19 January 2009 - 10:49 PM

thank you so very much and i'm sorry. Mr. Dude. =/ I didnt know where it went, so when i figured it out i tried to make a right one. Thnx again and i'll be sure to pay more attention to not messing up the board.
=]
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### #6 vzybilly

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## Re: Making a formula in excel

Posted 24 January 2009 - 09:08 PM

i'm guessing what you want is X = (-B ± √B² - 4AC)/2A

So, lets set up excel...(i always skip colum A and row 1)
B is in B2
A is in B3
C is in B4
"=" is in B5
"=D3 / (2 * B3)" is in B6, which will be X (+ side of ±)
"=D2 - (4 * B3 * B4)" is in D3
"=-B2 + √(B2 * B2)" is in D2
"=E3 / (2 * B3) is in B7, which will be X (- side of ±)
"=E2 - (4 * B3 * B4)" is in E3
"=-B2 - √(B2 * B2)" is in E2

i think i have the right meaning of ± and i'm not sure about √--- if that is the opposite of Y² which i think it pretty much Y / Y

then i would have to say change D2 & E2 to

"=-B2 + (D1 / D1)" is in D2
"B2 * B2" is in D1
"=-B2 - (D1 / D1)" is in E2

or if you want it all in one then(with the last change)
B6 is "=((-B2 + ((B2 * B2) / (B2 * B2))) - (4 * B3 * B4)) / (2 * B3)", which will be X (+ side of ±)
B7 is "=((-B2 - ((B2 * B2) / (B2 * B2))) - (4 * B3 * B4)) / (2 * B3)", which will be X (- side of ±)

im seeing if i can put it in to excel real quick...
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### #7 vzybilly

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## Re: Making a formula in excel

Posted 24 January 2009 - 09:32 PM

sorry to double post but here is the excel...
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### #8 [Lady♥Ada]

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## Re: Making a formula in excel

Posted 25 January 2009 - 09:08 PM

Thank you so very much. vzybilly <3
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### #9 vzybilly

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## Re: Making a formula in excel

Posted 26 January 2009 - 09:37 AM

could you check to see if the math is correct, i wasn't sure on 2 parts of it so i guessed...
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