The reaction 2Fe3+ + Ni(s) = 2Fe2+ + Ni2+ has equilibrium constant K = 1.5E34. What is the concentration of Fe3+ at equilibrium if a lot of Ni(s) is added to a 0.1 M solution of Fe3+ that initially contains no Fe2+?
The Attempt at a Solution
K = 4x3/(0.1-2x)2
My plan is to find x. [Fe3+] is then 0.1-x, but how do I solve this problem involving a cube root?