# Given that y = (x-a)/(x+b), express in terms of a, b and y

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• September 19th 2011, 03:00 AM
FailInMaths
Given that y = (x-a)/(x+b), express in terms of a, b and y
My working :

$y(x+b) = x-a$
$yx + yb = x-a$
$yx - x = -a - yb$
$x(y-1) = -a - yb$

Answer $x = (-a - yb)/(y-1)$

Do I need to further simplify?

Thanks for the help
• September 19th 2011, 04:15 AM
FernandoRevilla
Re: Given that y = (x-a)/(x+b), express in terms of a, b and y
Quote:

Originally Posted by FailInMaths
Do I need to further simplify?

More elegant :) : $x=\frac{a+by}{1-y}$ or $x=-b+\frac{a+b}{1-y}$ (euclidean division).
• September 19th 2011, 04:23 AM
FailInMaths
Re: Given that y = (x-a)/(x+b), express in terms of a, b and y
Quote:

Originally Posted by FernandoRevilla
More elegant :) : $x=\frac{a+by}{1-y}$ or $x=-b+\frac{a+b}{1-y}$ (euclidean division).

Hmm but is my answer mathematically correct above? I get confuse and messed up often when I move around with negative numbers
• September 19th 2011, 04:24 AM
FernandoRevilla
Re: Given that y = (x-a)/(x+b), express in terms of a, b and y
Quote:

Originally Posted by FailInMaths
Hmm but is my answer mathematically correct above? I get confuse and messed up often when I move around with negative numbers

Yes, your answer is correct.
• September 19th 2011, 04:43 AM
FailInMaths
Re: Given that y = (x-a)/(x+b), express in terms of a, b and y
Quote:

Originally Posted by FernandoRevilla
Yes, your answer is correct.

Thanks! =)