what is the slope and what does it represent in this problem

Question

Ely's family is taking a road trip. They are paying $150 for someone to look after their dog while they are gone. They also expect to pay $200 per day fro meals and hotel and $80 per day for other expenses. 

Answer 1

Let Y = Total amount payable after X days

 

Y = (200 +80 )X + 150 = 280 X + 150

 Here the slope is 280 , payable per day apart from fixed $ 150