It should be
=(B1/A1-C1)/(1-B1/A1)

sorry for the typo...
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"Sheeloo" wrote:

if you just need to calculate z for each set of x,y and a then use a formula...
enter x values in Col A, y in B and a in C then enter this in D1 and copy down
=(B1/A1-1)/(1-B1/A1)
[check my solution and correct if wrong, but you get the idea, right?]
You can enter as many sets as you want, one set per row... and copy down the
formula in D1



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"Simon Jowitt" wrote:

Hi, I have an equation in the following form: x = (y*(z+1))/(z+a) which I
have the values for x, y and a, but need to find a value for z. I can do this
one at a time using the SOLVER add-in - but is there another way around this?
or can you run multiple versions of solver e.g. to determine 100+ values of z
for 100+ different equations? even 20+ would do!