They mean is.B = If the new car will have a price to 4.6354 hundred thousand baht.B = the number of years if car use increased to 1 year car price will decrease 0.5104 hundred thousand baht.
Meaning a b = new cars if the price reaches 4.6354 billion baht b = if the car has a number of years, the first increase in vehicle prices are down 0.5104 billion baht.