HELP PLEEES ASAP i am so lost

The sum of the first eight terms of an arithmetic progression is 9m + 14. the fifth term of the06 progression is 2m - 6, where m is a constant.given that the first term of the progression is 26,find the value of the common difference, d and thevalue of m.

Ineed to know the ordered pairs for this equation i need the answer quick because it’s a timed test

While on a train trip, marsha noticed that there were 35 people in her train car. after the next stop, there were only 21 people in her car. if p represents the percent decrease in the number of people in marsha's train car, what is p?