Respuesta :

sqdancefan

Answer:

  D(9, 1)

Step-by-step explanation:

A being the midpoint means its coordinates satisfy ...

  A = (E + D)/2

Solving for D, we find ...

  D = 2A -E

  = 2(4, 5) -(-1, 9) = (2·4 +1, 2·5 -9)

  D = (9, 1)