Answer:
(a). The image distance is 13.77 cm to the left side of a lens.
(b). The magnification of the image is -0.655
Step-by-step explanation:
Given that,
Object distance u= 21.0 cm
Focal length f= -40.0 cm
(a). We need to calculate the image distance
Using formula of lens

Put the value into the formula




(b). We need to calculate the magnification of the image
Using formula of magnification

Put the value into the formula


Hence, (a). The image distance is 13.77 cm to the left side of a lens.
(b). The magnification of the image is -0.655