8. Given $x, y \in \mathbf{R}$, and $|5 x+y|+|5 x-y|=20$, then the maximum value of $x^{2}-x y+y^{2}$ is $\qquad$ , and the minimum value is $\qquad$ .
8. 124,3

The equation $|5 x+y|+|5 x-y|=20$ represents a rectangle on the coordinate plane, bounded by the lines $y=\pm 10, x=\pm 2$. At the upper left or lower right corner of the rectangle, $x^{2}-x y+y^{2}$ attains its maximum value; at the upper right or lower left corner, it attains its minimum value.