I just need to make sense out of elasticities and how to determine if a good is normal or inferior.
I have determined by $X_1$ which is in the form $m/p_1 - p_1/p_2$, that I should just take the derivative with respect to $m$ to get a value, which is always negative, and by that logic a normal good. But what does it mean when the demand of a good doesn't have $m$ in its function?