Chemistry Thermodynamics question?

Question

Approximate the heat of the reaction for the following equation using Hess's Law:

N2H4 (l) + H2O2 (l) --->N2 (g) + 4 H2O (l)
Change in Hrxn=?
(1) N2H4 (l) + O2 (G) --->N2 (g) + 2 H2O (l)
Change in Hrxn= -622.2kJ
(2) H2 (g) + O2 (g) ---> H2O2 (l)
Change in Hrxn= -187.8 kJ
(3) H2 (g) + 1/2 O2 (g) ---> H2O (l)
Change in Hrxn= -285.8 kJ

I was sick the day we did this in class so i have no idea... but this is how it is written in the work

Answer 1

The eqn should be

N2H4 (l) + 2 H2O2 (l) --->N2 (g) + 4 H2O (l)

Its Hrxn = (1) - 2*(2) + 4*(3) = -1389.8 kJ