Notice that you are predicting negative prices for small gross areas. Does that make sense (Please come and live in this appartment, I will give you money if you do). I would consider using a log link function. 

As for the categorical variable, I would just add indicator variables for the number of bathrooms instead of entering it as a continuous variable. 

Multivariate Linear Regression with continuous and discrete explanatory variable
In Gakuen Alice, Yuka Azumi stole Narumi's Alice when she was running away. Consequently, he lost all ability to love her or anyone else. How does this work?
