Answer:
The coordinates of endpoint K are (-2,-3)
Explanation:
Midpoint
Given two points J(jx, jy) and K(kx, ky), the coordinates of the midpoint M(mx,my) are given by:


We are given the coordinates of M and need to find the coordinates of K. From the equations above, solve for kx and ky:


The points are M(6,3) and J(14,9), thus:


The coordinates of endpoint K are (-2,-3)