7x - (3x + 7)....not simplified
7x - 3x - 7 =
4x - 7....simplified
        
             
        
        
        
If the problem is 3(15x - 17), none of those expressions are correct. You would multiple the 3 to each term (hence the "distributive" part) to get 45x - 51. 
        
             
        
        
        
Answer: 8
Step-by-step explanation:
 
        
             
        
        
        
Answer:
a ">"
Step-by-step explanation:
3 to the power negative one (-1) is the same as 1/3 (one unit divided by 3). 
1/4 on the other hand is one unit divided by 4.
Dividing one object into three parts (think for example a chocolate bar) gives you a larger (greater) piece than dividing it into four equal pieces.
Therefore 1/3  > 1/4
 
        
             
        
        
        
X - 5
Y - 7 
That is the answer hope this helps !