I'm currently doing a lab to calculate the enthalpy of formation for $\ce{MgO}$. However at the moment me and my lab partner are having a disagreement. We've both calculated and agreed upon the same heat released in the reactions ($\pu{4.2\frac {kJ}{mol}}$ (reaction of $\ce{MgO +2HCl})$ and $\pu{7.5\frac {kJ}{mol}}$ (reaction of $\ce{Mg +2HCl}$)). Where we disagree is over how to calculate the enthalpy of reaction.
My argument:
Enthalpy is the amount of energy put into the reaction, what we measured is the heat released thus the equation should be: $$\Delta H=-\frac{Q}{n}$$ Also, this would make sense considering our reactions were blatantly exothermic, and using this equation provides negative values.
Her argument:
The equation is simple and the teacher agreed with her results: $$\Delta H=\frac{Q}{n}$$
My question: Who is correct?