If Mark (m) is 8 years older than Susan (s), which expression represents Mark's age? A-8+s
B-8s
C-m-8
D-s-8

for finding the midpoint of any given 2 pair of points simply add the respective x coordinates with other x coordinate and the y coordinate with other y coordinate and divide them by 2

in your question it will be :

(3+1)/2 for the x coordinate of mid point i.e 2

[8+(-4)]/2 for the y coordinate of midpoint i.e 2

so coordinates of mid point of points (3,8) and (1,-4) will be (2,2)

hope this is what you were asking for!

step-by-step explanation: