8. Let real numbers $x, y$ satisfy
$$
\left\{\begin{array}{l}
x-y+1 \geqslant 0, \\
y+1 \geqslant 0, \\
x+y+1 \leqslant 0 .
\end{array}\right.
$$

Then the maximum value of $2 x-y$ is
8. 1 .

When $x=0, y=-1$, $2 x-y$ takes the maximum value 1.