Instructions : Find EX if JX = 17 plz help I don’t understand

Given f(x) = 17-x^2what is the average rate of change in f(x) over the interval [1, 5]?

Problem fathi wants to print out a pdf document that is 48 pages long. to save paper, he decides to print on both sides of each sheet and to print two pages on each side of the sheet. how many sheets of paper will he need?

Can someone me out here and the tell me the greatest common factor