How to solve

$14\mathrm{.}28.$ Consider the reactions

$\frac{1}{2}{N}_2(g)+\frac{1}{2}{O}_2(g)NO(g)$

$\frac{1}{2}{N}_2(g)+O_2(g)N{O}_2(g)$

If these reactions come to equilibrium after combustion in an internal$-$combustion engine at $2000K$ and $200$ bar, estimate the mole fractions of $NO$ and $N{O}_2$ present for mole fractions of nitrogen and oxygen in the combustion products of $0\mathrm{.}70$ and $0\mathrm{.}05.$