Answer: The required co-ordinates of the midpoint S are (-1.5, 2).
Step-by-step explanation: Given that S is the midpoint of a line segment QR, where the co-ordinates of he endpoints are Q(-5, 5) and R(2, -1).
We are to find the co-ordinates of the midpoint S.
We know that
the co-ordinates of the midpoint of a line segment with endpoints (a, b) and (c, d) are
![\left(\dfrac{a+c}{2},\dfrac{b+d}{2}\right).](https://tex.z-dn.net/?f=%5Cleft%28%5Cdfrac%7Ba%2Bc%7D%7B2%7D%2C%5Cdfrac%7Bb%2Bd%7D%7B2%7D%5Cright%29.)
Therefore, the co-ordinates of the point S are
![\left(\dfrac{-5+2}{2},\dfrac{5+(-1)}{2}\right)\\\\\\=\left(\dfrac{-3}{2},\dfrac{4}{2}\right)\\\\=(-1.5,2).](https://tex.z-dn.net/?f=%5Cleft%28%5Cdfrac%7B-5%2B2%7D%7B2%7D%2C%5Cdfrac%7B5%2B%28-1%29%7D%7B2%7D%5Cright%29%5C%5C%5C%5C%5C%5C%3D%5Cleft%28%5Cdfrac%7B-3%7D%7B2%7D%2C%5Cdfrac%7B4%7D%7B2%7D%5Cright%29%5C%5C%5C%5C%3D%28-1.5%2C2%29.)
Thus, the required co-ordinates of the midpoint S are (-1.5, 2).