They gave you the formula for doing this! Just substitute the x and y to the corresponding formula.
Order pairs: (7, 5) and (3, 3)
Work: x1 = 7
x2 = 3
y1 = 5
y2 = 3
Now substitute.
1.) (7 + 3)/2 = 10/2
5 = x
2.) (5 + 3)/2 = 8/2
4 = y
Answer: The midpoint is B. (5, 4)
