M^3-8n^3 factor the sum and difference

Tim's phone service charges $23.06 plus an additional $0.22 for each text message sent per month. if tim's phone bill was $28.56, which equation could be used to find how many text messages, x, tim sent last month?

At a book fair, joe bought 24 books at 3 for $5 and had $2 left. how much money did he have at first?

If f (x) = 2x2 +5/(x-2), complete the following statement: f(6) =