Hey there! I'm happy to help!
To find the x value of the midpoint, you add the x values and divide by 2.
-7+6=-1
-1/2=-1/2
For the y value, you add the y values and divide by 2.
-7-8=-15
-15/2=-7 1/2
Therefore, our midpoint is (-1/2, -7 1/2).
Have a wonderful day! :D