A10.0 cm object is 5.0 cm from a concave mirror that has a focal length of 12 cm. what is the distance between the image and the mirror?

Let's use the mirror equation to solve the problem:

where f is the focal length of the mirror, the distance of the object from the mirror, and the distance of the image from the mirror.
For a concave mirror, for the sign convention f is considered to be positive. So we can solve the equation for by using the numbers given in the text of the problem:



Where the negative sign means that the image is virtual, so it is located behind the mirror, at 8.6 cm from the center of the mirror.