The coordinates of B is (1,-3) .
It is given that midpoint of AB is (3, -1) and coordinates of A is (5, 1) .
Let the coordinate of B be (x, y) .
By using midpoint formula , we get
[tex](3, -1)=(\frac{5+x}{2} , \frac{y+1}{2} )\\[/tex]
On comparing , we get the x- coordinate
[tex]\frac{5+x}{2} =3\\\5+x=6\\x=1[/tex]
On comparing , we get the y- coordinate
[tex]\frac{1+y}{2} =-1\\\\1+y=-2\\y=-3[/tex]
Hence , the coordinates of B is (1,-3) .
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