Please answer this :l I don’t know how to do it

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

Carlos spent 1 1/4 hours doing his math homework he spent 1/4 of his time practicing his multiplication facts how many hours to carlos been practicing his multiplication facts

In a singing competition, there are 150 participants. at the end of each round, 40% of the participants are eliminated. how many participants are left after n rounds?