Answer:
a. -8 cm
Explanation:
[tex]d_{o}[/tex] = distance of the object = 4 cm
[tex]d_{i}[/tex] = distance of the image = ?
[tex]f[/tex] = focal length of the converging lens = 8 cm
using the lens equation
[tex]\frac{1}{d_{o}} + \frac{1}{d_{i}} = \frac{1}{f}[/tex]
[tex]\frac{1}{4} + \frac{1}{d_{i}} = \frac{1}{8}[/tex]
[tex]d_{i}[/tex] = - 8 cm
