Question 54805
:

{{{y=xz/(x+z)}}}
:
Mult equation by (x+z), gets rid of the denominator and you have:
y(x + z) = xz
:
yx + yz = xz
:
Subtract xz and yz from both sides and you have:
yx - xz = - yz
:
Factor out x
x(y - z) = -yz
:
Divide both sides by (y-z) and you have:
:
{{{x = - (yz)/(y-z)}}}