Access denied for user 'root'@'localhost - Mysql - Linux Ubuntu

EDIT: I HAVE TRIED ALL THE OTHER TOPICS THAT IS ALREADY HERE ON STACKOVERFLOW, BUT I CANT FIX

When I try to do something here on MYSQL, I cant and the same shows me this message:

This when I click on "local instance 3306":

This when i click on "local instance 3306"

and this when i try to test a new connection

and this when i try to test a new connection