Image height and position-converging lens

Question

A 1.0-cm-tall object is 12 cm in front of a converging lens that has a 35 cm focal length.

1. Calculate the image position.
2. Calculate the image height.

Answer 1

1. 1/35 = 1/12 + 1/f; f = - 18.26 cm (in front of lens)
2. h/1 = 18.26/12; h = 18.26/12 = 1.52 cm