The midpoint of line segment LN, point M, is located at (0, 3). One of the endpoints, N, is located at (-8, -1).
What are the coordinates of the other endpoint, L?

To find a missing endpoint: find the slope of the line and (essentially) “add it” to the midpoint

slope formula: m = y2-y1/x2-x1
substitute: -1 - 3/-8 - 0 = -4/-8 = 1/2
m = 1/2

so the rise is 1 and the run is 2. now for the “adding”

the midpoint is at (0,3). the x value is 0 and they y value is 3. add the rise to the y value (as they are both going vertically) to get 4. add the run to the x value (as they are both going horizontally) to get 2.

now just make it into coordinates: (x,y) = (2, 4)

your missing endpoint is (2,4).