Step-by-step explanation:
5z, 5x and 5y are all unlike terms. 
If there was something like <em><u>5z</u></em> + 5x <em><u>-</u></em><em><u> </u></em><em><u>3z</u></em> + 5y, then both 5z and -3z have something in common and so therefore are said to be like terms. 
Hope my description helps.
Good night.
 
        
             
        
        
        
Answer:
I think it sould be 16m
Step-by-step explanation: