The reaction for the formation of gaseous hydrogen fluoride from hydrogen and fluorine has an equilibrium constant of 1.15x10^2 at a given temperature. In a particular experiment, 3.0 mol of each component was added to a 1.5 L flask. What is the equilibrium concentration of hydrogen fluoride?

So I did 3/1.5L= 2M

H2 + F2 -------> 2HF
2 2 0
-x -x +2x

2x /(2-x)^2 = 1.15 x 10^2

From here, I don't really know how to solve for x to where the HF concentration would equal 5.056 M, which is the right answer.