Answer:
Given that P is the midpoint of line segment NQ, and the coordinates of Q are (3, 9), we can find the coordinates of the missing endpoint N using the midpoint formula. The midpoint formula states that the coordinates of the midpoint of a line segment are the average of the coordinates of the two endpoints.
FORMULA:
(x, y) = ( (x1 + x2)/2, (y1 + y2)/2 )
SUBSTITUTE:
(x, y) = ( (3 + (-1))/2, (9 + 5)/2 )
(x, y) = (1, 7)
Therefore, the missing endpoint of line segment NQ is (1, 7).