Equation using 2 4 1 that equals 15

What is the average rate of change for this function for the interval from x=2 to x=4 ?

Isuck at math ; ^; m a student solved this problem and said the answer is 3 feet. chase had a roll of ribbon that contained 7 7/8  feet of ribbon. he cut off one piece that was 3 5/8  feet long and another piece that was 1 1/4  feet from the roll. how much ribbon was left on the roll? is the student's answer reasonable? yes, the answer is reasonable. no, the answer is not reasonable. it should be about 2 feet. no, the answer is not reasonable. it should be about 13 feet. no, the answer is not reasonable. it should be about 4 feet.

The probability that an adult possesses a credit card is .70. a researcher selects two adults at random. by assuming the independence, the probability that the first adult possesses a credit card and the second adult does not possess a credit card is: