Click picture to see full - First open your Facebook page via iPhone and click the top left icon with 3 horizontal bars.
Next - type in the name of the friend you wish to UNfriend/delete OR click friends to scroll through names
When you've pulled up a person's page click the box just under their profile picture (it has a check mark next to it).
Finally - click UNfriend and...BOOM, now you don't have to see their posts or pictures! (For the record, this friend was an example and will be not be deleted)
The creator of this guide has not included tools