Can someone please explain this to me?

How do i do this? i don’t understand

At the beginning of the day, stock xyz opened at $6.12. at the end of the day, it closed at $6.88. what is the rate of change of stock xyz? a. 1.17% b. 11.0% c. 12.4% d. 81.5%

Question: a) does the given set of points represent a linear function? how do you know? b) assume that the point (-2,4) lies on the graph of a line. what y-values could complete this set of ordered pairs that lie on the same line: (- (hint: there are several correct answ