The formula of a midpoint:
[tex]M\left(\dfrac{x_1+x_2}{2};\ \dfrac{y_2-y_1}{2}\right)[/tex]
We have:
[tex](6,\ -2)\to x_1=6,\ y_1=-2\\\\M(8,\ 1)[/tex]
Substitute:
[tex]\dfrac{6+x_2}{2}=8\ and\ \dfrac{-2+y_2}{2}=1[/tex]
First equation:
[tex]\dfrac{6+x_2}{2}=8\ \ \ |\cdot2\\\\6+x_2=16\ \ \ |-6\\\\x_2=10[/tex]
Second equation:
[tex]\dfrac{-2+y_2}{2}=1\ \ \ \ |\cdot2\\\\-2+y_2=2\ \ \ |+2\\\\y_2=4[/tex]
Answer: The coordinates of point B are (10, 4).
