What are key features of a linear function?

Key features of a linear function is a function is linear if it’s graph forms a straight line, the line is straight because the variables change at a constant rate, they have a constant rate of change

On april 20, 1814, the dethroned emperor left france for the isle of  elba, where he was exiled under the terms of the treaty of fontainebleau.napoleon  would be allowed to ruleelba, which had 12,000 inhabitants. perhaps cruelly, the treaty allowed him to retain the title "emperor."