Since you don't provide the coordinates of the point W, I will help you in a general form anyway. In the Figure below is represented the segment that matches this problem. We have two endpoints U and V. So, by using the midpoint formula we may solve this problem:
![Midpoint=W=W((x_(1)+x_(2))/(2), (y_(1)+y_(2))/(2))=W(x_(3), y_(3)) \\ \\ where:\\ \ U=U(x_(1), y_(1)) \ and \ V=V(x_(2), y_(2)) \\ \\ and: \\ x_(3)=(x_(1)+x_(2))/(2) \\ y_(3)=(y_(1)+y_(2))/(2)](https://img.qammunity.org/2019/formulas/mathematics/middle-school/xz417j7284qkq3vp35fbx4lcrkwnzhszgu.png)
Therefore:
![x_(2)=2x_(3)-x_(1) \\ y_(2)=2y_(3)-y_(1)](https://img.qammunity.org/2019/formulas/mathematics/middle-school/s9r9uf1svxitnjn0q7aotjwayagfgv0h6o.png)
So we know
but we also must know
![x_(1) \ and \ y_(1)](https://img.qammunity.org/2019/formulas/mathematics/middle-school/q7duy1nurm9b69x5c57lpfwn3rf4jkh3j8.png)
Finally, knowing the points U and W we can find the endpoint V.