Answer:
5cm 
Step-by-step explanation:
It is the pythagorean Theorem and there is this special rule my teacher always told me to follow that means it is always 3, 4, and 5. Trust me, I had this problem before. It is 5cm just use the pythagorean theorem. 
 
        
             
        
        
        
Answer: 7 Boxes
Step-by-step explanation: 
There are 4 classrooms and 29 boxes of markers. So, you would divide 29 by 4 which is 7.25. Then, you need to round it because you don't have a quarter of a box. So, each classroom will get 7 boxes.
I hope that helps!
 
        
                    
             
        
        
        
Answer:
Step-by-step explanation:
5x² -  10x - 7 + 5x² + 8 = 5x² + 5x² -10x - 7 + 8
                                     = 10x² - 10x + 1
Bring like terms together and add/ subtract the like terms
 
        
             
        
        
        
 Answer:
This is a function, because for every x-value, there is exactly one y-value.
The domain is: {-5, -4, -3, -2}, and the range is {-2, -1, 0}
Let me know if this helps!