ok.. i got solve to give me a solution. but it only works symbolically. as soon as i asign values to all the variables (apart from p and T of course), i get an empty result. any ideas why? -florian

solve does return a solution!? i tried solve but i didn't give me any result. can you tell me the exact solve command you used? i used: c1 := 1.438786e-02: c2 := 1.191062e-22: h := 6.626e-34: c := 2.998e8: k := 1.381e-23: trans_7 := 1-0.0785704: trans_21 := 1-0.1546972: lambda_7 := 2.11e-6; lambda_21 := 3.99e-6; PolynomialSystem({L_fire_7, L_fire_21},{T,p}); thanks for your help!