[michaelt817]

At a certain temperature, K = 9.1  10-4 for the following reaction.

FeSCN2+(aq) reverse reaction arrow Fe3+(aq) + SCN -(aq)
Calculate the concentrations of Fe3+, SCN -, and FeSCN2+ in a solution that is initially 4.0 M FeSCN2+.

ok so im not sure how to choose which answer after solving the quadratic equation.

9.1e-4 +/- sqroot(-9.1e-4)^2- 4(1)(.00364)/ 2(1)... this equals 9.1e-4 +/- .120664825 / 2(1)

For + i get .06078 (right answer)
For - i get .059877

NVM I put the - part wrong in the calculator.. DELETE!!