Answer
$i=-4.8cm$
Work Step by Step
Since the lens is diverging, the focal length is negative (f=-12cm). Use the lens equation $$\frac{1}{f}=\frac{1}{i}+\frac{1}{p}$$ to solve for $i$; $$\frac{1}{i}=\frac{p}{pf}-\frac{f}{pf}$$ $$\frac{1}{i}=\frac{p-f}{pf}$$ $$i=\frac{pf}{p-f}$$ Substituting values of $f=-12cm$ and $p=8.0cm$ yields an image distance of $$i=\frac{(8.0cm)(-12cm)}{8.0cm+12cm}=-4.8cm$$
