Question

Need help with midpoint formula? Question: If the midpoint between (x, 3) and (9, 9) is (7, 6), find the value of x.

Could you please show how to do this/what formula you use? I know the midpoint formula but my teacher acted like there's a different one needed to find the value of x as opposed to just finding the midpoint and I don't understand!

Answer 1

Midpoints are quite simple really the midpoint of (x2,y2) to (x1,y1) is just the average of the coordinates...

((x1+x2)/2, (y1+y2)/2) in this case you are only given one point and the midpoint and you really looking for the other endpoint so...

And we are only concerned with the x value so:

(x+9)/2=7

x+9=14

x=5