# Math Help - rearranging for x

1. ## rearranging for x

Many thanks to anyone who can help solve this little bugger

Rearrange for x, so x=?

x/(x-a)=(x-b)/(x-c)

Workings and an explanation would be handy if available

381

2. Originally Posted by tomh381
Many thanks to anyone who can help solve this little bugger

Rearrange for x, so x=?

x/(x-a)=(x-b)/(x-c)

Workings and an explanation would be handy if available

381
The answer is 381? You must be withholding some information from us.

3. Originally Posted by tomh381
Many thanks to anyone who can help solve this little bugger

Rearrange for x, so x=?

x/(x-a)=(x-b)/(x-c)

Workings and an explanation would be handy if available

381
Cross multiply

$x(x-c) = (x-b)(x-a)$

then expand

$x^2 - cx = x^2 - (a+b)x + ab$

cancel and move all x terms to the left

$(a+b-c)x = ab$

then isolate x

$x = \frac{ ab}{a+b-c}$

4. the question is written:

Reaarange the subject of the following,

x/(x-a)=(x-b)/(x-c) Rearrange for "x"

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A similar question would be: Rearrange for "s"

a=ut+0.5st^2 original arrangment

a-ut=0.5st^2 minus "ut" from each side

(a-ut)/t^2=0.5s divide each side by "t^2"

2((a-ut)/t^2)=s divide by "0.5" so multiply by 2

^ represents a power so 2^2 = 2 squared

Hope this helps.

Thanks, 381

5. Originally Posted by tomh381
Many thanks to anyone who can help solve this little bugger

Rearrange for x, so x=?

x/(x-a)=(x-b)/(x-c)

Workings and an explanation would be handy if available

381
Thread closed. Pre-emptive action due to questions in other threads getting deleted.