Answer:
it is 7
Step-by-step explanation:
Given points are the same, so midpoint also will be the same:
[tex]M_{AB}=\left(\dfrac{x_A+x_B}2\,,\ \dfrac{y_A+y_B}2\right)=\left(\dfrac{9+9}2\,,\ \dfrac{7+7}2\right)=\left(9\,,\ 7\right)\\\\x_M=9\,,\quad y_M=7[/tex]
