$\begin{align}  & \text{Let the term of the G}\text{.P}\text{. be }\frac{a}{r},a,ar \\ & \text{Product of the }G.P=\frac{a}{r}\times a\times ar=1,\text{  }a=1 \\ & \text{Sum of the }G.P=\frac{a}{r}+a+ar=-\frac{7}{3} \\ & \frac{a+ar+a{{r}^{2}}}{r}=-\frac{7}{3}-----(i) \\ & \text{Substitute }1\text{ for }a\text{ in }(i)\text{  }\frac{1+r+{{r}^{2}}}{r}=-\frac{7}{3} \\ & 3+3r+3{{r}^{2}}=-7r \\ & 3{{r}^{2}}+10r+3=0,\text{  }(3r+1)(r+3)=0 \\ & r=-3\text{ or }r=-\frac{1}{3} \\ & \text{The }G.P=-\frac{1}{3},1,-\frac{1}{9}\text{ or }-3,1,-9 \\\end{align}$