A(-1,2)b(-7,4) find the midpoint of ab

The midpoint would be (-4,3)

You can find the mid point of the two by adding both the x's then divid by 2 and add both the y's and divide by 2 for example.

-1+(-7) =-8
-8/2 =-4
x= -4

2+4 = 6
6/2 =3
y=3

So the mid point is (-4,3) 

Use a graph site then you will find your answer