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sev Just gettin' started!
Joined: 06 Apr 2007 Posts: 26
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Posted: Tue Apr 10, 2007 6:04 pm Post subject: So I fully realize I need to brush up on my Algebra.. but... |
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So im getting the the point where I can set up the problems, but the alebra.. it's been a long time..
how do you solve the following? Does it require FOIL?
14s=6s^2 |
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Neo2000 Managing Director
Joined: 27 Jan 2007 Posts: 280
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Location: India Test Date: 30/09 Target GMAT Score: 710
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Posted: Sun Apr 15, 2007 12:13 am Post subject: |
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All you have to ensure is that you perform the same mathematical operation on both sides to get "s" all by itself and you'll be fine
Divide by s on both sides
14 = 6s
Divide by 6 on both sides
s = 14/6 = 7/3 |
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Stacey Koprince Resident GMAT Expert
Joined: 27 Dec 2006 Posts: 956
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Location: Bay Area, California
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Posted: Tue Apr 17, 2007 12:00 am Post subject: |
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That is not all you have to ensure, unfortunately. That method will find you ONE factor, but not all of them. If you are ever trying to find factors (or values for a particular variable), do NOT divide out the variable you are supposed to solve for - or you will lose a factor (typically zero).
This is a quadratic so we first to set everything equal to zero:
14s=6s^2
0 = 6s^2 - 14s
then, factor out (NOT divide out) an s
0 = s(6s-14)
now set each factor equal to zero
0 = s
0 = 6s-14 => 14 = 6s => 14/6 = s
So 7/3 is one factor, but 0 is also a factor. _________________ Stacey Koprince
GMAT Instructor
Director of Corporate Development, Northern California
Manhattan GMAT
Contributor to Beat The GMAT! |
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