Difference between statement x=+5 and x+=5

You have written, as part of a school assignment, a research paper on the solar system. you want to share this paper on your school website. on which type of server will you upload it?

Singing in the rain: this first part of the film shows the early history of motion picture. how accurate do you think the portrayal of the early motion picture industry is? why? is historical accuracy important in films and theater productions? explain.

Im doing this last minute and literally none of my neighbors or people that my dad works with use excel so if anyone could me make up an example