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Given: Object distance, u = -45 cm

Image distance, v = +90 cm (real)

Height of the object, = 2 cm

We need to calculate the Focal length

Applying the lens formula which is given as:

Since, focal length is positive, so the lens is convex lens.

Magnification is given by the following relation;

Also, the magnification is given by the ratio of height of image to the height of object.

So,

The negative sign shows that the image is inverted.