If M (5, 2.5) is the midpoint of line XY and X is (-4, 1) and Y = (a, 4), what is the value of a?

Question

i honestly have no idea how to do this and i need help asap! thanks!

Answer 1

If M (5, 2.5) is the midpoint of line XY and X is (-4, 1) and Y = (a, 4), what is the value of a?

Moving from point X to point M, the x coordinate changes from -4 to 5: 9
In that same move, the y coordinate changes from 1 to 2.5: 1.5

Moving the same distance from point M to point Y, the y coordinate would
also change by 1.5, from 2.5 to 4, as stated.
Therefore, the x coordinate would change by 9, from 5 to 14.

That would make the coordinates of Y (14, 4), so the value of a is 14.