What is the relation between distance of object distance of image and focal length for spherical mirror?

State the relation between object distance, image distance and focal length of a spherical mirror (concave mirror or convex mirror).

The relation between the object distance (u), the image distance (v) and the focal length (f) of a spherical mirror (a concave or convex mirror) is: 

`1/v+1/u=1/f`

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