Calculate the standard enthalpy of formation of solid diboron trioxide (B2O3) using the following thermochemical information:
B2O3(s) + 3 H2O(l) B2H6(g) + 3 O2(g) H = +2147.5 kJ
2 H2(g) + O2(g) 2 H2O(l) H = -571.7 kJ
2 B(s) + 3 H2(g) B2H6(g) H = +35.4 kJ