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October 22, 2025, 12:52:41 pm
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Author Topic: 2 questions !!  (Read 589 times)  Share 

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Homer J

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2 questions !!
« on: January 24, 2011, 08:18:16 pm »
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could i please have some help guys !

1) make n the subject of the formula r= mns/p(n+1)

2) solve for x and y

   (1-a)x-(b-1)y=a-b
   ax+2(b-1)y = ab-2a

thanks
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Andiio

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Re: 2 questions !!
« Reply #1 on: January 24, 2011, 08:20:57 pm »
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1)

r = mns/p(n+1)
rp(n+1) = mns
rpn + rp = mns
rpn - mns = -rp
n(rp-ms) = -rp
n = -rp/(rp-ms)
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Re: 2 questions !!
« Reply #2 on: January 24, 2011, 09:56:12 pm »
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I assume you're not allowed to use the CAS for question 2.

For this question, all you need to do is to set up the matrices for the simultaneous equation and find the det. Everything should factorise out nicely. I don't know how to type matrices with Latex (and I so have a cut on my finger so it's really hard to type) so pardon me :P
You should get determinant =

after some hardcore algebra expansion.

Do some cancellations and you should end up with x = -b and y = -a
Hope that's right.
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