Yarrr maths.....very tough subject 
        
             
        
        
        
The graph of f(x) is a straight line passing through points (0, -7) and (7, 0)
        
             
        
        
        
Answer:
300 days of work.
Step-by-step explanation:
He needs to work for 300 days for 2 dollars a day to get 600 dollars:
300 x 2 = 600
 
        
                    
             
        
        
        
I would be the origin, constant of proportionality, and the unit rate.