Help me with this question

Let f (x) = x e8x. find a formula for the nth derivative of f, where n is any positive integer. use x and n in your answer if needed. f (n)(x) =

Pam buys a sleeve of ball bearings for her skateboard. each of the bearings is 1 1/5 inches wide. the sleeve is 9 3/5 inches long. how many ball bearings are in the sleeve? show your work.

Sam opened a money-market account that pays 3% simple interest. he started the account with $7,000 and made no further deposits. when he closed the account, he had earned $420 in interest. how long did he keep his account open?