S(s)+O2(g)→ SO2(g)+x kJ;2SO3(g)→ 2SO2(g)+O2(g)-y kJ;From the above data, calculate the heat of formation of SO3 (in kJ/mole)

S(s)+O2(g)→ SO2(g),    ∆H=-x kJ; ........(1)2SO3(g)→ 2SO2(g) + O2(g),      ∆H=+y kJ; ........(2)SO3(g)→ SO2(g)+12O2(g),     ∆H=+y2 kJ; .......(3)Eq (1) - Eq (3)Ss+32O2g→SO3g, ∆H=-x+y2