Find the coordinates of the other endpoint

Point​ A is located at (-1,-5). The midpoint of ​line segment AB is point C (2,3).

What are the coordinates of point B?

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The x-coordinate of the midpoint is found by adding the x-coordinates of the endpoints
together, and dividing by 2.

(-1,-5) is the given endpoint and (2,3) is the midpoint
2 = (-1 + x)/2  
4 = -1 + x   {multiplied each side by 2}
x = 5  {added 1 to each side}
5 is the x-coordinate of the other endpoint


The y-coordinate of the midpoint is found by adding the y-coordinates of the endpoints
together, and dividing by 2.

(-1,-5) is the given endpoint and (2,3) is the midpoint
3 = (-5 + y)/2
6 = -5 + y   {multiplied each side by 2}
y = 11   {added 5 to each side}
11 is the y-coordinate of the other endpoint

The other endpoint is (5,11)

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