The re action catalyzed by carbamoyl phosphate synthetase is

H₄⁺ + H₃⁻ + 2ATP→2 ADP + P + Carbamoyl-p

This reaction has 3 reactants and 3 products as shown above

At equilibrium in the cell, the following values are found forect

ATP = 1m
ADP = 2m
P = 3m
Carbamoyl-P=0.5m
H⁺ =0.25m
H⁻ =5m

What is the Keq for this reaction?