Given that

and

, if

is an arithmetic sequence, then the common difference between successive terms is

.
You then have




So the explicit formula for the

th term is
So if they lost 2 yards on the first play and on the following three plays they lost 2 yards they lost 4 yards total because it doesnt say they lost 2 yards on each of the three play so they would only lose 4 yards
2.5418x10^12
you do 9x9x9x9x9x9x9x9x9x9x9x9x9