1: Traditional Programming: you have rules and data come in and answers that come out. It is manual and hardcoded input of rules. Machine Learning: you have answers and data aka labeling come in and rules that match one to the other come out. Algorithm is used so it is not manual.
2: The outputs are different because of how the algorithm guesses/predicts.
3: The 4 bedroom house is the best deal and the 3 bedroom house is the worse deal. In my model the predicted value was subtracted with the actual price and the lowest number (most negative tells me that that house had the best deal, which was the 4 bedroom house) and vice versa for the 3 bedroom house.