1. Let $x, y$ be real numbers, and $2 x^{2}+x y+2 y^{2}=2$. Then the range of values for $x^{2}-5 x y+y^{2}$ is $\qquad$ .
$$
\text { II. 1. }\left[-\frac{6}{5}, \frac{14}{3}\right]
$$

Let $x^{2}-5 x y+y^{2}=k$, then
$$
\begin{array}{l}
2 k=2 x^{2}+x y+2 y^{2}-11 x y=2-11 x y \\
x y=\frac{2-2 k}{11} \\
2(x+y)^{2}=2+3 x y=2+\frac{3(2-2 k)}{11} \\
\geqslant 0, \Rightarrow k \leqslant \frac{14}{3} \\
2(x-y)^{2}=2-5 x y=2-\frac{5(2-2 k)}{11} \\
\geqslant 0, \Rightarrow k \geqslant-\frac{6}{5} .
\end{array}
$$