Question

segment PR has an endpoint at (25, -5) and a midpoint of (18, -1). What is the value of the x-coordinate of the other endpoint?

Answer 1

The x- and y-coordinates of the midpoint of a line segment are the average values of the x- and y-coordinates of the endpoints, respectively.

Answer 2

I'm not quite understanding. What would be the first step?

Answer 3

It's simpler if you see it.
Let's say you have point A(5, 10) and point B(15, 20) as endpoints of a segment.
To find its midpoint, all you do is add the x's and divide by 2, and add the y's and divide by 2.
The midpoint is M( (5 + 15)/2 , (10 + 20)/2 ) = M(10, 15)

Answer 4

so I would take 25 and subtract 18?

Answer 5

Here you know one endpoint and the midpoint.
So add the x-value, 25, of the endpoint to unknown x, divide the whole thing by 2 and set equal to 18. Then solve for x.