What is the change in enthalpy of the first reaction below, given the enthalpies of the other two reactions? Here's the reactions:

There was a formatting issue with the specific chemistry symbols, there all correct in the picture below

2C(s) + O2(g) → 2CO(g)

C(s) + O2(g) → CO2(g) ∆H0= -394 KJ/mol

CO(s) + 1/2 O2(g) → CO2(g) ∆H0= -283 KJ/mol

There was a formatting issue with the specific chemistry symbols, there all correct in the picture below