PLEASE HELP!! H2 and Br2 are heated to give HBr according to the equation below:
H2(g)+Br2(g)-->2HBr(g)

at equilibrium, at a specific temperature, the concentration of H2 is 0.133 mol/L, the concentration Br2 is 0.121 mol/L, and the concentration HBr is 0.712 mol/L. Calculate the equilibrium constant for this reaction at that specific temperature.
*do not put units in the answer box. round to the nearest hundredths place.*