What does proportional mean and also can somebody me with the attachments

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) =

On saturday a souvenir shop had 125 customers.sixty four percent of the costumers paid with a credit card. how many costumers paid with cash?

Given δjkl : δxyz, find x. a)10 b)12 c)16 d)20