What are the coordinates of point B?

Question

What are the coordinates of point B of segment DB, if D (-5,9) and midpoint M (2,-1)?

Answer 1

if the coordinates of B are (x, y). then mid point term is
[(x - 5)/2 , (y +9)/2] = (2, -1)
comparing its x and y coordinates as follows

x - 5 = 4 ==== > x = 9
y + 9 = -2 ==== > y = -11

Answer 2

Take each coordinate one at a time. x starts at -5 and halfway there x is 2, so it went up 7. To get to the other half it will go up 7 more, to 9.

y started at 9 and halfway there it was at -1 so it went down 10. To get to the other half it would go down 10 more, to -11.

So B = (9,-11)

Answer 3

x: You go from -5 to 2 by 7 steps. Going another 7 steps, you get 9.
y: You go from 9 to -1 by -10 steps. Going another -10 steps, you get -11.

Therefore, B(9,-11) is the answer.