maths- i hate algebra!!!!!

[befuzzled!!]

this section has smart people maybe they can help
i have a problem i have to rearrage the formula to make P the subject but it isn't working!!! someone please answer this question and show the workings ahhhh!
A 1
-- = ------
P 1+P
A over P equals 1 over 1+P
PLEASE BEFORE I TEAR MY HAIR OUT!!!!

[newtron]

A/P = 1/(1+P)
(1+P)A/P =1 Multiply both sides by (1+P)
(1+P)/P = 1/A Divide both sides by A
1/P+1 = 1/A Expand fraction on LHS to 2 fractions with P as the denominator
1/P = (1/A)-1 Subtract 1 from both sides
1=((1/A)-1)P Multilpy both sides by P
P = 1/((1/A)-1) Divide both sides by ((1/A)-1)

I hope this helps.

[befuzzled!!]

i think you missed something

[befuzzled!!]

i'm just gonna ask my maths teacher

[kitcatkitten]

I could be really wrong as I haven't done algebra in years but the answer I got was p=a/(1-a)
P equals a over (one minus a)

I did it like this:
1) multiply by p to give a = p / (1+p)
2) multiply by (1+p) to give a(1+p) = p
3) expand brackets to give a + ap = p
4) rearrange to give p - ap = a
5) take p out of the brackets on the left hand side so you have p (1-a) = a
6) then finally divide by (1-a) to give p = a/(1-a)

I hope this is ok, i'm pretty sure it works

[newtron]

my answer:
P=1/((1/A)-1)

is equivalent to the answer provided by kitcakitten.

[chakka35]

Cross-multiplying gives you:

A +AP = P

Taking AP over to the other side gives:

A = P - AP = P(1 - A)

Taking 1 - A over to the other side gives:

A/(1 - A) = P

[Cathyhuns]

Both answers are the same.

P=1/((1/A)-1)
Multiply top and bottom of of both sides by A (which has no effect) gives
AP/A=A/((A/A-A)
P=A/(1-A)

[kitcatkitten]

The answers are the same but p = 1/((1/a)-1) is pretty messy - i'd go with p = a/(1-a)