An open cylinder with internal radius r cm has a 2-cm wall and is 9r cm long. Express the volume of material in the wall of the cylinder as a polynomial function in terms of r

answer: hence, function will be

explanation:

since we have given that

cost of a new textbook = $85

according to question, the resale value of a textbook decreases by 25% with each previous owner,

so, our function becomes,

here, y is the total value of the text book after x owners.

hence, function will be