Please help like by the end of today plz

Recall the definition of a polynomial expression. find two polynomial expressions whose quotient, when simplified,is. use that division problem to determine whether polynomials are closed under division. then describe how theother three operations-addition, subtraction, and multiplication-are different from division of polynomials.

Which is an equation for the nth terms of the sequence 12,15,18,21

What is the product? a-3/15a × 5/a-3