Answer:
As shown in picture, if MC is median of triangle ABC, M is midpoint of AB.
Denote the coordinate of A, B and M are (Ax, Ay), (Bx, By) and (Mx, My) respectively.
The formula relating coordinate of A, B and M is:
Ax + Bx = 2Mx
Ay + By = 2My
In detail,
-1 + Bx = 2 x 4 => -1 + Bx = 8 => Bx = 9
11 + By = 2 x 11 = > 11 + By = 22 => By = 11
=> Option D is correct
Hope this helps!
:)
