1. ## Equation

How do I put z = x/ (x + y) in terms of x?

2. ## Re: Equation

It's a simple problem dude!

Rewrite it as proportion

$\dfrac{z}{1}=\dfrac{x}{x+y}\\ \text{Now, apply cross multiplication} \\ x=z(x+y) \\ x=xz+yz \\ x-xz=yz \\ x(1-z)=yz\\ x=\dfrac{yz}{(1-z)}\tag*{}$

3. ## Re: Equation

$z = \dfrac{x}{x+y}$

$(x+y)z = x$

$x z + y z = x$

$y z = x-xz$

$y z = x(1-z)$

if $z\neq 1$ then $x = \dfrac{y z}{1-z}$

if $z=1$ then $y=0$ and $x$ can equal anything other than 0.