Heating copper(II) oxide at 400C does not produce any appreciable amount of Cu:) CuO(s) CuO(s) +

Question:

Heating copper(II) oxide at 400°C does not produce any appreciable amount of Cu:)
CuO(s) ⇌ CuO(s) + ½ O2(g) G° = 127.2 kJ/mol
However, if this reaction is coupled to the conversion of graphite to carbon monoxide, it becomes spontaneous. Write an equation for the coupled process and calculate the equilibrium constant for the coupled reaction.