Can someone help me with this question?

Find the average rate of change for f(x) = x2 − 3x − 10 from x = −5 to x = 10.

Pat listed all the numbers that have 15 as a multiple write the numbers in pats list

Jack has a piece of red ribbon that is two times as long as his piece of blue ribbon. he says that he can use two different equation to find out how long his piece of red ribbon is compared to his piece of blue ribbon is. is he correct? explain his reasoning