Help I have no clue what this is

Define multiplicative inverse. give an example of a number and its multiplicative inverse.

Including 6% sales tax, an inn charges $135.68 per night. find the inns nightly cost

Afarmer has a large field that is x feet in length. he wants to fence in a rectangular section in the middle of the field , leaving a length of 100 feet of open field behind each end of the fenced rectangle. he also wants the width of the fenced-in space to be 100 feet less than its length. find the expressions to represent the length and width of the fenced section of the field