@Axel Vogt, I also have noticed that diference compared to other two equations, but in the original article formula is written as noted. I guess it's a typo but, since I'm not definitely sure, I wrote as it is.

:)

It is a system used to calculate free testosterone, estradiol and dihydrotestosterone in serum sample.

This looks great. Thank you all for efforts and quick replies.

:)

@Kitonum if I type solve({eq1, eq2, eq3}, useassumptions), assuming (fE2 > 0, fT > 0, fDHT > 0) it outputs (with same inputs i.e. f(1,2,3,4,5)):

{fE2 = 3.02872370166550*10^(-10), fT = 1.90199449982479*10^(-10), fDHT = 0.300792608887318e-5}, {fE2 = 7.15539742720000*10^10, fT = 3.30345789526199, fDHT = 4.72656319086592*10^14}

First one is, in your example, among 10 solutions, but second is totaly new. I've intended to use assumption just to extract results >0 but, instead of that, I have got a new result. Isn't it supposed to get a solution using assumptions just as a subset of solutions without assuming?

Sorry for being boring. :)

Thanks again.

@Kitonum Thanks for so quick help.

It works like a charm. :)