# how do i solve this for x y = x/(x+z)

• Jun 26th 2012, 03:05 PM
lukebond
how do i solve this for x y = x/(x+z)
how do i solve this for x

y = x/(x+z)

really bugging me. Is it possible. If you need more information on it i can explain what I'm trying to work out.

If i have an amount which i will call z and i want to add another amount to it which i will call x but i want the amount x to be a certain percentage of x + z. The certain percentage is y represented as a number less than 1.

.25 = 5/(5+15)

25%

i want to be able to take the percentage and the original amount and find out what x need to be to match the original amount to the percentage y.

Any help would be much appreciated.
• Jun 26th 2012, 03:09 PM
Plato
Re: how do i solve this for x y = x/(x+z)
Quote:

Originally Posted by lukebond
how do i solve this for x
y = x/(x+z)

Can you solve $(x+z)y=x$ for $x~?$
• Jun 26th 2012, 03:10 PM
lukebond
Re: how do i solve this for x y = x/(x+z)
To be honest. No. But i would love an explanation or a point in the right direction.
• Jun 26th 2012, 03:16 PM
lukebond
Re: how do i solve this for x y = x/(x+z)
I can expand the brackets but i can't seem to merge the x together.
• Jun 26th 2012, 03:21 PM
HallsofIvy
Re: how do i solve this for x y = x/(x+z)
y = x/(x+z)

1. Multiply on both sides to get y(x+ z)= x.

2. Expand the bracket to get yx+ yz= x.

3. Subtract both yz and x from both sides to get yx- x= -yz

4. Factor x out on the left to get (y- 1)x= -yz.

5. Divide both sides by y- 1.
• Jun 26th 2012, 03:28 PM
lukebond
Re: how do i solve this for x y = x/(x+z)
Is there anywhere i can find out more about the factor out step or can you just give me a quick explanation. And thanx alot this is exactly what i wanted.
• Jun 26th 2012, 03:46 PM
Plato
Re: how do i solve this for x y = x/(x+z)
Quote:

Originally Posted by lukebond
Is there anywhere i can find out more about the factor out step or can you just give me a quick explanation. And thanx alot this is exactly what i wanted.

Yes there is a way. Learn basic graded school algebra.
But know that this is not a tutorial service.
• Jun 26th 2012, 04:09 PM
lukebond
Re: how do i solve this for x y = x/(x+z)
Its ok I get it now.