So the midpoint formula is [tex] (\frac{x_2+x_1}{2} ,\frac{y_2+y_1}{2} ) [/tex] . Using our information, our two equations are going to be[tex] \frac{x-4}{2}=0 [/tex] and [tex] \frac{y-5}{2}=-10 [/tex] .
Starting with the x-coordinate, multiply both sides by 2: [tex] x-4=0 [/tex]
Next, add both sides by 4 and your answer will be [tex] x=4 [/tex]
Next with the y-coordinate, its going to be pretty much the same process:
[tex] \frac{y-5}{2}=-10\\ y-5=-20\\ y=-15 [/tex]
Putting everything together, our other endpoint is (4,-15).
