Chemical Equilibrium

The equilibrium constants for the reactions \(a, b\), and \(c\) are as given:

a) \(\mathrm{N}_2+3 \mathrm{H}_2=2 \mathrm{NH}_3: \mathbf{K}_1\)

b) \(\mathrm{N}_2+\mathrm{O}_2=2 \mathrm{NO}: \mathrm{K}_2\)

c) \(2 \mathrm{H}_2+\mathrm{O}_2=2 \mathrm{H}_2 \mathrm{O}: \mathbf{K}_3\)

What would be the Equilibrium constant for the reaction:

\(4 \mathrm{NH}_3+5 \mathrm{O}_2=4 \mathrm{NO}+6 \mathrm{H}_2 \mathrm{O} ; \mathbf{K}_{\mathbf{x}}\)