Answer: -33255 + 30
Step-by-step explanation:
 
        
             
        
        
        
Three that are equivalent are 12:9 8:6 28:21
        
             
        
        
        
Right away we know we don't have fractions; the midpoint is the average of the coordinates, so if it and one endpoint are integers so is the other endpoint.
We can do a kind of point arithmetic:
C = (A+B)/2
2C = A+B
B = 2C - A
B = 2(6,1) - (1,3) = (12,2)-(1,3)=(11,-1)
Answer: That's none of the above, but a typo away from the first choice.
 
        
             
        
        
        
A . 2/10 + 5/10= 7/10
B. 3/10 + 4/10= 7/10
C. 6/10 + 1/10 =7/10