Equilibrium: Keq Values

Consider the following equilibria:
2HBr(g)H2(g)+Br(g)Kc,12HBr_{(g)} \rightleftharpoons H_{2(g)} +Br_{(g)} \hspace{20pt} K_c,_1
2H2O(g)2H2(g)+O(g)Kc,22H_2O_{(g)} \rightleftharpoons 2H_{2(g)} +O_{(g)} \hspace{20pt} K_c,_2
The equilibrium constant for the reaction:
2HBr(g)+12O2(g)H2O(g)+Br2(g)Kc,32HBr_{(g)} + \frac{1}{2} O_{2(g)} \rightleftharpoons H_2O_{(g)}+Br_{2(g)} \hspace{20pt} K_c,_3
is:
More Solving for K in Different Scenarios Questions: