Simply it as follows:
1 + 39 = 40
2 + 38 = 40 etc
18 + 22 = 40
19 + 21 = 40
There are 19 of these plus 40 itself . . .therefore 20 of them
20 x 40 = 800
And finally the last number not used, 20
Therefore 800 + 20 = 820
        
                    
             
        
        
        
Answer:
Not Sure
Step-by-step explanation:
The slope is 0.
See graph below...
 
        
             
        
        
        
Answer:
yeah 
Step-by-step explanation:
it's right i think tell me if not if not I'm sorry