(2,-8)
Explanation
The rule for a rotation by 180° about the origin is:
[tex](x,y)\Rightarrow(-x,-y)[/tex]in other words you have to change the sign of x component and y component, so
[tex](-2,8)\Rightarrow rotated\text{ 180 \degree}\Rightarrow(-(-2),-(8))=(2,-8)[/tex]so, the point that results is
(2,-8)
I hope this helps you