Hello, this is a problem from Israel Gelfand's Algebra book about polynomials.

Problem 152. The polynomial gives a remainder of when divided by . Find the remainder when is divided by .

My try: We know that where Q is the quotient, this is the same as , I see that all I have to do is to rewrite this equation to something like this , I tried dividing both sides by but I can't get the form of .

Thanks in advance.