Finding related functional dependencies from Amstrong's axioms
This is rather easy. 

AB → C
B → D

therefore:

AB → C
AB → D

and:

AB → CD


Next:

AB → CD
CD → E

therefore:

AB → E

with: AB → C
we get:

AB → CE


And finally:

CE → GH

thus:

CE → G

and with the (previous): AB → CE

AB → G