Verified answer

Xm=(Xa+Xb/2, Ya+Yb/2)

Xm=(7-2/2, 9+5/2)

Xm=(5/2, 14/2)

Xm=(5/2, 7) <----------------- Coordenadas do ponto médio.

M(x,y)

x=(7-2)/2

x=5/2

y=(9+5)/2

y=14/2

y=7

M(5/2, 7)