Hey guys! I'm really lost on this equation. Any help?

Question

H2(g) yIelds 2H(g)  
Delta  H = 436 kJ/mol
F2(g) yields  2F(g)            
DeltaH = 158 kJ/mol
H(g)  + F(g) yields HF(g)           DeltaH = -568 kJ/mol
Calculate deltaH for:
H2(g) + F2(g) yields  2 HF(g)

Answer 1

1 H2(g) yIelds 2H(g)
Delta H = 436 kJ/mol
2 F2(g) yields 2F(g)
DeltaH = 158 kJ/mol
3 H(g) + F(g) yields HF(g) DeltaH = -568 kJ/mol
Calculate deltaH for:
H2(g) + F2(g) yields 2 HF(g)

Bold face I have numbered the equations.
Add eqn 1 to eqn 2 and add twice the equation 3. That gives the equation you want. So dH rxn will be dH1 + dH2 + 2*dH3 = ?