Explain whether an editorial article in a newspaper, expressing the views of the editor, should be classified as a valid source of information.

Editorial articles in any publication always express the opinions of the writer or groups of writers behind the article. Therefore, these pieces are not generally considered to be valid sources of information, which should rely on facts, not opinions.

Of course it should.  It's the best available source of information
regarding the opinions of the editor and nothing else, and that's
exactly how it should be used.

Efficiency is an action of doing something. for example when you take a test. good efficiency means you did well but bad effeciency or no effiency means you did bad.

The charge of an ion with 55 protons and 52 electrons is +3. the reason is because protons are positive, and there are three more than the amount of negative electrons.