Confusion about DX & FX Lenses

Its not about the lens its all about the sensor size, the DX lens is made to fit the size of the DX sensor. so if you use an FX lens on a DX body, the DX body i.e DX sensor will use the inner part of the FX lens, there will be no change in focal length.

On the other hand FX bodies have an option called crop factor, in order to allow you the use of the DX lenses on the FX body but this means it will have the same FOV of using the same DX lense on a DX body.

Thank You Mr. Sergio Spain for a well done explanation, guys if you still don't get it photography is not for you pic an easier hobby