You can't successfully photograph or scan a negative (using a conventional flat-bed scanner, such as those in all-in-one printers) because camera and conventional scanners rely on reflected light. (i.e. light is bounced off the surface of an object and then captured by the camera or scanner). To view or scan a negative you need to use transmitted light, which is passed through the film itself.
Ideally you should take negative to a High Street photo processing firm, such as Snappy Snaps or Max Spielmann, where they'll be able to use a dedicated film scanner (which passes light through negatives, rather than bouncing it off them) to scan the negative and produce a print.
To get a rough idea of what's on the negative though, if you've got a phone or camera that can focus on small objects, you could try placing a light source
behind the negative and then taking a photograph of it. (One way to do that might be to tape the negative to a window, taking care to ensure that the tape only comes into contact with the very edges of the negative). You could then transfer the image to your computer and use any image editor that's got an 'invert' function. My own choice would be to use Irfanview:
https://www.irfanview.com
(The option is available at Image > Negative (invert image) > All Channels)