1. If the geometric sequence $\left\{a_{n}\right\}$ satisfies $a_{1}-a_{2}=3, a_{1}-a_{3}=2$, then the common ratio of $\left\{a_{n}\right\}$ is $\qquad$
Let $\left\{a_{n}\right\}$ have a common ratio of $q$, then $\left\{\begin{array}{l}a_{1}(1-q)=3, \\ a_{1}\left(1-q^{2}\right)=2\end{array} \Rightarrow 1+q=\frac{2}{3} \Rightarrow q=-\frac{1}{3}\right.$.