Energetics question help

Hi i am having a hard time understanding this question, could someone perhaps guide me as to how to go through it, thanks.

Q1. Calculate the enthalpy of formation of butane (C4H10) from the following data: Enthalpy of combustion of graphite = -393.6 kJmol-1 Enthalpy of combustion of hydrogen = -285.9 kJmol-1 Enthalpy of combustion of butane = -2877.1 kJmol-1

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