Standard enthalpy of formation of gaseous diborane

Question

Assignment:

Calculate the standard enthalpy of formation of gaseous diborane, B₂H₆, using the following thermochemical information: (Hints: (i) Standard states of B₂O₃ and B are solid, (ii) Look carefully at equations 1 and 2 and what they describe)

Equa. 1.     4B(s) + 3O2(g)  →  2B2O3(s)                              ΔH°₁ = -2509.1 kJ

Equa. 2.     2H2(g) + O2(g)   →     2H2O(l)                             ΔH°₂ = -571.7 kJ

Equa. 3      B2H6(g) + 3O2(g)  →   B2O3(s) + 3H2O(l)             ΔH°₃ = -2147.5kJ

Provide complete and step by step solution for the question and show calculations and use formulas.