Since point S (-1, -3) is the midpoint of the segment AB, the coordinates of point B are (-7, -14).
In order to determine the midpoint of a line segment with two (2) end points, we would add each end point together and then divide by two (2):
![Midpoint=((x_1+x_2)/(2) ,(y_1+y_2)/(2) )](https://img.qammunity.org/2021/formulas/mathematics/college/aed97t4sgygtpmnrso2mqrjbdvire8tp04.png)
Next, we would determine the coordinate of B on line segment AB with midpoint S at (-1, -3). Let us substitute our given values into the midpoint formula as follows;
![(-1,-3)=((5+x_2)/(2) ,(8+y_2)/(2) )](https://img.qammunity.org/2021/formulas/mathematics/college/qc30mdv7jqx4of3rmdgjcilu7h398sivxp.png)
By setting up two equations to solve for our tow unknowns x₂ and y₂;
![-1=(5+x_2)/(2)\\\\-2=5+x_2\\\\x_2=-5-2\\\\x_2=-7](https://img.qammunity.org/2021/formulas/mathematics/college/ty3ll5tf6gvyv00tmjrxadzyz02ob79jut.png)
Therefore, the x-coordinate of end point B is -7.
For the y-coordinate of end point B on line segment AB, we have the following:
![-3=(8+y_2)/(2) \\\\-6=8+y_2\\\\y_2=-6-8\\\\y_2=-14](https://img.qammunity.org/2021/formulas/mathematics/college/iikmuivchjrvngtc49gcmtjcoyzf0zbl7z.png)
In conclusion, the coordinates of point B are (-7, -14).
Complete Question:
The point A (5, 8) is given. Determine the coordinates of point B, knowing that the point S (-1,-3) is the midpoint of the segment AB.