Ok this is a linear equation that is descending and is in slope intercept form
        
             
        
        
        
Answer:
The answer should be A. Y= -4x -9
 
        
             
        
        
        
Let's find out how much she spent every month.
4000 (starting money) - 2800 (remaining money) = 1200 spent over 3 months
1200/3 = 400 per month was spent
So if she continues to spend 400 a month?
How many months are left? 12 (months of the year) - 3 (months she already spent) = 9
So 9 (remaining months) * 400 (amt per month) = 3600 she'll spend at the going rate over 9 months.
But she only has 2800 left. 
2800 (remaining) - 3600 (estimated total of spending) = -800
So she will be 800$ in debt at the end of the year at the current rate.
        
             
        
        
        
X=5 because 4x5=20 and 20-4=16