Given,
The focal length of the lens, f=-39 cm
The object distance, o=30 cm
From the thin lens formula,
[tex]\frac{1}{f}=\frac{1}{i}+\frac{1}{o}[/tex]On rearranging the above equation,
[tex]\frac{1}{i}=\frac{1}{f}-\frac{1}{o}[/tex]On substituting the known values,
[tex]\begin{gathered} \frac{1}{i}=\frac{1}{-39}-\frac{1}{30} \\ =-0.06 \\ i=\frac{1}{-0.06} \\ =-16.67\text{ cm} \end{gathered}[/tex]Thus the image distance is -16.67 cm
