Respuesta :

Step-by-step explanation:

Using vectors

DE = EF

e - d = f - e

Collect like terms

-d = f - 2e

Multiply both sides by -1

d = 2e - f

d = 2(-1,6) - (2,9)

d = (-2,12) - (2,9)

d = (-4,3)

This is the missing endpoint.

Hope this helps :-)

Answer:

(-4,3)

Step-by-step explanation:

(x1 + 2)/2 = -1

x1 = -4

(y1 + 9)/2 = 6

y1 = 3

So, the other endpoint is (-4,3) .